Proximity sensor circuits and related sensing methods

Abstract

To provide proximity sensors.SOLUTION: At least one of the proximity sensors includes a first dielectric layer, an electrically conductive layer, and an electrode. The first dielectric layer includes an inner surface and an outer surface. The electrically conductive layer is located proximate to one of the inner surface and the outer surface of the first dielectric layer. The electrode includes an outer surface. The outer surface of the electrode is located proximate to the inner surface of the first dielectric layer. The outer surface of the electrode and the electrically conductive layer define a gap.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 62 / 910,125, filed October 3, 2019, entitled "Proximity Sensor Circuit and Related Sensing Method," the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present disclosure generally relates to proximity sensors and related sensing methods for detecting hemodynamic changes (or pulse waveforms) in a user. Summary of the Invention

[0003] In one general aspect, the present disclosure provides a proximity sensor. The proximity sensor includes a first dielectric layer, an electrically conductive layer, and an electrode. The first dielectric layer includes an inner surface and an outer surface. The electrically conductive layer is located proximate to one of the inner surface or the outer surface of the first dielectric layer. The electrode includes an outer surface. The outer surface of the electrode is located proximate to the inner surface of the first dielectric layer. The outer surface of the electrode and the electrically conductive layer define a gap.

[0004] In another aspect, the proximity sensor further comprises a foam layer.

[0005] In another aspect, the proximity sensor further comprises a sealing layer disposed over the sensing surface.

[0006] In another aspect of the proximity sensor, the electrically conductive layer is located proximate to an inner surface of the first dielectric layer, and the proximity sensor further includes a second dielectric layer disposed between the electrode and the electrically conductive layer, wherein the outer surface of the electrode and the electrically conductive layer define a gap.

[0007] In another embodiment of the proximity sensor, the second dielectric layer has a thickness of less than 3 μm.

[0008] In another embodiment of the proximity sensor, the second dielectric layer has a textured surface.

[0009] In one general aspect, the present disclosure provides a proximity sensor. The proximity sensor includes a first dielectric layer, an electrically conductive layer, a sensing electrode, and a reference electrode. The first dielectric layer includes an inner surface and an outer surface. The electrically conductive layer is located proximate to one of the inner surface or the outer surface of the first dielectric layer. The sensing electrode is located proximate to the inner surface of the first dielectric layer. The sensing electrode includes an inner surface and an outer surface. The outer surface of the sensing electrode is located proximate to the inner surface of the first dielectric layer. The outer surface of the sensing electrode and the electrically conductive layer define a gap. A reference electrode is disposed relative to the sensing electrode. The reference electrode is located proximate to the inner surface of the first dielectric layer. The reference electrode includes an inner surface and an outer surface. The outer surface of the reference electrode is located proximate to the inner surface of the first dielectric layer. The outer surface of the reference electrode and the electrically conductive layer define a gap.

[0010] In another aspect, the reference electrode is disposed laterally relative to the sensing electrode, laminated relative to the sensing electrode, or mechanically separated from the sensing electrode.

[0011] In another embodiment, the proximity sensor further comprises a fifth dielectric layer disposed between the reference electrode and the first dielectric layer.

[0012] In another aspect, the proximity sensor further comprises a sixth dielectric layer disposed between the sensing electrode and the first dielectric layer.

[0013] In another aspect, the proximity sensor further comprises a foam layer, with the sensing electrode and the reference electrode located on opposite sides of the foam layer.

[0014] In one general aspect, the present disclosure provides a proximity sensor module. The proximity sensor module includes a sensor element substrate, at least one electrically conductive electrode, an electronics module, at least one electrically conductive pad, and at least one elastically deformable electrically conductive feature. The sensor element substrate includes a proximity sensor as described herein. At least one electrically conductive electrode lead is disposed on the sensor element substrate. The at least one elastically deformable electrically conductive feature is disposed on the at least one electrically conductive electrode lead or the at least one electrically conductive electrode pad. The at least one electrically conductive pad is disposed on the electronics module. The at least one electrically conductive pad is positioned to create an electrical connection between the at least one electrically conductive lead and the at least one electrically conductive pad through the at least one elastically deformable electrically conductive feature.

[0015] In one general aspect, the present disclosure provides a circuit for measuring a physiological parameter. The circuit includes a sensor circuit, a conversion circuit connected to the sensor circuit, and a signal detection circuit. The sensor circuit includes a sensor element substrate including any one of the proximity sensors described herein. The sensor element includes at least one electrode. The sensor circuit is configured to monitor a capacitance signal between the at least one electrode and a user's skin. The capacitance signal represents movement, pressure, and / or electric field modulation, which may be due to a pulse wave event, a change in pressure or blood flow in the user's blood vessel, or movement of a part of the user's body. The conversion circuit is connected to the sensor circuit. The conversion circuit is configured to convert the monitored capacitance signal into a digital signal indicative of the monitored capacitance signal. The signal detection circuit is configured to receive the digital signal and determine at least one physiological parameter associated with the user.

[0016] In another aspect of the circuit, the physiological parameters include blood pressure, systolic, diastolic, mean arterial pressure, pulse pressure, respiration rate, or combinations thereof, and their variability, both as time series values ​​and trends.

[0017] In another aspect of the circuit, the signal detection circuit is configured to filter the sensor data for use in extracting a blood pressure value or to provide a quality assessment of the subsequent sensor data for estimating a confidence level for the extracted value.

[0018] In one general aspect, the present disclosure provides a circuit for measuring a physiological parameter. The circuit includes a sensor circuit, a conversion circuit connected to the sensor circuit, and a signal detection circuit. The sensor circuit includes a sensor element substrate including any one of the proximity sensors described herein. The sensor circuit includes at least one electrode. The sensor circuit is configured to monitor a capacitance signal between the at least one electrode and a user's skin. The capacitance signal represents movement, pressure, and / or electric field modulation, which may be due to a pulse wave event, a change in pressure or blood flow in the user's blood vessel, or movement of a part of the user's body. A conversion circuit is connected to the sensor circuit and configured to convert the monitored capacitance signal into a digital signal indicative of the monitored capacitance signal. The signal detection circuit is configured to implement blood pressure and other hemodynamic and physiological models.

[0019] In another aspect of the circuit, the signal detection circuit is configured to convert the capacitance signal into a format that can be displayed on an external monitor and / or processed and stored on an external data system.

[0020] In another aspect of the circuit, the signal detection circuit is configured to take inputs obtained from a prescribed starting schedule in which sensors are applied and then used at multiple locations.

[0021] In one general aspect, the present disclosure provides a method for hemodynamic monitoring via a wearable device. The wearable device includes a sensor circuit having at least one electrode, a conversion circuit for receiving a signal from the sensor circuit, converting the signal to a digital signal, and providing the digital signal to a signal detection circuit for processing the digital signal. The method includes sensing a capacitance signal via the sensor circuit using the at least one electrode. The capacitance signal represents a pressure and / or electric field modulation that may result from a pulse wave event or a change in pressure or blood flow within a user's blood vessel. The method further includes converting the sensed capacitance signal into a digital signal indicative of the sensed capacitance signal, providing the digital signal to the signal detection circuit, processing the digital signal representing the capacitance changes over time to generate pulse waveform data, correlating the pulse waveform data with various hemodynamic parameters, processing the pulse waveform data, and determining the hemodynamic parameter based on the pulse waveform data.

[0022] In another aspect, the method further includes reducing motion artifacts at the accessory device.

[0023] The above description / summary is not intended to describe each aspect or every implementation of the present disclosure. The following figures and detailed description also illustrate various aspects. [Brief explanation of the drawings]

[0024] Various exemplary aspects may be more fully understood when the following detailed description is considered in conjunction with the accompanying drawings.

[0025] [Figure 1] 1 illustrates an exemplary proximity sensor having a floating foil structure with a dielectric layer separating a sensing electrode from an electrically conductive layer in accordance with at least one aspect of the present disclosure.

[0026] [Figure 2]1 illustrates an exemplary proximity sensor having a floating foil structure with a separate dielectric layer separating a sensing electrode from an electrically conductive layer to control the distance between the electrically conductive layer and the sensing electrode, in accordance with at least one aspect of the present disclosure.

[0027] [Figure 3] 1 illustrates an exemplary proximity sensor having a floating foil structure with an adhesive layer formed around the periphery of the sensing electrode elements or around the entire sensing electrode array in accordance with at least one aspect of the present disclosure.

[0028] [Figure 4] 1 illustrates an exemplary proximity sensor having a floating foil structure with a dielectric, foam, or double-sided tape disposed over the sensing electrode lead in accordance with at least one aspect of the present disclosure.

[0029] [Figure 5] 1 illustrates an exemplary proximity sensor having a floating foil structure with a reference electrode and a sensing electrode in accordance with at least one aspect of the present disclosure.

[0030] [Figure 6] 1 illustrates an exemplary proximity sensor having a floating foil structure with a layer of dielectric material attached to or coated onto a reference electrode, the layer being significantly thicker and / or having a significantly lower dielectric constant than the material used in the sensing electrode, in accordance with at least one embodiment of the present disclosure.

[0031] [Figure 7] 1 illustrates an exemplary proximity sensor having a floating foil structure with a foam layer disposed between the sensor element and an attachment structure, such as a wristband, to provide conformability and ensure that both the reference element and the sensing element have similar contact with the skin, in accordance with at least one aspect of the present disclosure.

[0032] [Figure 8]1 illustrates an exemplary proximity sensor having a floating foil structure with a reference electrode positioned on an opposite side of a foam substrate layer from a sensing electrode, in accordance with at least one aspect of the present disclosure.

[0033] [Figure 9] 1 shows one diagram of an example mounting structure for a proximity sensor having a floating foil structure, where the mounting structure includes a band, patch, or multiple materials used in other ways to secure the sensor array to the skin, according to at least one aspect of the present disclosure.

[0034] [Figure 10] 10 illustrates a cross-sectional view of the exemplary mounting structure shown in FIG. 9 taken along section line 10--10, in accordance with at least one embodiment of the present disclosure.

[0035] [Figure 11] 11 shows a detailed view of a cross-sectional view of the exemplary mounting structure shown in FIG. 10 taken along line 11, in accordance with at least one aspect of the present disclosure.

[0036] [Figure 12] 1 illustrates an example of re-engageable contact between an electronic module and a sensor / electrode lead of a proximity sensor having printed conductive elastomeric conductive bumps for resiliently compressible re-engageable contact, in accordance with at least one aspect of the present disclosure.

[0037] [Figure 13] 1 illustrates an exemplary method for printing conductive elastomeric bumps for resiliently compressible reengageable contacts in accordance with at least one aspect of the present disclosure.

[0038] [Figure 14] 10 illustrates an example of a conductive elastomeric bump printed on an electrode lead that is pressed against an electronic module, in accordance with at least one aspect of the present disclosure.

[0039] [Figure 15]1 shows an example of a conductive elastomeric bump produced by embossing a structure into a substrate supporting an electrode, in accordance with at least one aspect of the present disclosure.

[0040] [Figure 16] 1 shows an example of a conductive elastomeric bump produced by mechanically deforming an electrical lead, in accordance with at least one aspect of the present disclosure.

[0041] [Figure 17] 1 illustrates an exemplary method of forming a connection between an electronic module and a sensor array by mechanically deforming an electrical lead, in accordance with at least one aspect of the present disclosure.

[0042] [Figure 18] 18 illustrates an exemplary connector formed by the method of FIG. 17 having individual electrode leads mechanically separated in an array of electrode leads with improved compatibility, in accordance with at least one aspect of the present disclosure.

[0043] [Figure 19] 18 illustrates an exemplary connector formed by the method of FIG. 17 having mechanically rigid spring fingers optionally supported and / or deformed with foam or other spacer material, in accordance with at least one embodiment of the present disclosure.

[0044] [Figure 20] 20 illustrates an example of a mating contact on an electronic module for use with the connector shown in FIG. 19, in accordance with at least one embodiment of the present disclosure.

[0045] [Figure 21]An exemplary band for an adult is shown that is adjustable in size to fit radial, brachial, tibial, dorsal, and / or femoral pulse points, and the band containing reusable electronics may be utilized with disposable sensors through the use of a sealed or partially sealed electronic module that resides in a tray, and a multi-component case is assembled around the electronics and secured through known fastening methods in accordance with at least one aspect of the present disclosure.

[0046] [Figure 22] 22 illustrates a cross-sectional view of the adult band shown in FIG. 21 in accordance with at least one embodiment of the present disclosure.

[0047] [Figure 23] 1 illustrates an exemplary band for an infant that is adjustable in size to fit radial, brachial, tibial, dorsal, and / or femoral pulse points in accordance with at least one aspect of the present disclosure.

[0048] [Figure 24] 23 illustrates a cross-sectional view of the infant band shown in FIG. 22, according to at least one embodiment of the present disclosure.

[0049] [Figure 25] 1 illustrates a block diagram of an electronic device in accordance with at least one aspect of the present disclosure.

[0050] [Figure 26A] 1 illustrates an example of a sensor circuit and a sense signal circuit in accordance with at least one aspect of the present disclosure. [Figure 26B] 1 illustrates an example of a sensor circuit and a sense signal circuit in accordance with at least one aspect of the present disclosure.

[0051] [Figure 27A] 10 illustrates an example of a device and the resulting interaction with a user's skin in accordance with at least one aspect of the present disclosure. [Figure 27B] 10 illustrates an example of a device and the resulting interaction with a user's skin in accordance with at least one aspect of the present disclosure. [Figure 27C]10 illustrates an example of a device and the resulting interaction with a user's skin in accordance with at least one aspect of the present disclosure. [Figure 27D] 10 illustrates an example of a device and the resulting interaction with a user's skin in accordance with at least one aspect of the present disclosure.

[0052] [Figure 28] 1 is a block diagram illustrating an example method for implementing electronics and / or signal flow from a device in accordance with at least one aspect of the present disclosure.

[0053] [Figure 29A] 1 illustrates various exemplary devices in accordance with at least one aspect of the present disclosure. [Figure 29B] 1 illustrates various exemplary devices in accordance with at least one aspect of the present disclosure.

[0054] [Figure 30A] 1 illustrates an exemplary device having a packaged array of sensors including multiple (eg, four) electrodes with different capacitive sensitivities in accordance with at least one aspect of the present disclosure. [Figure 30B] 1 illustrates an exemplary device having a packaged array of sensors including multiple (eg, four) electrodes with different capacitive sensitivities in accordance with at least one aspect of the present disclosure.

[0055] [Figure 31A] 1 illustrates an apparatus according to at least one aspect of the present disclosure. [Figure 31B] 1 illustrates an apparatus according to at least one aspect of the present disclosure. [Figure 31C] 1 illustrates an apparatus according to at least one aspect of the present disclosure.

[0056] [Figure 32A] 10 shows exemplary data collected using the device and data collected using an arterial line, according to various experimental embodiments. [Figure 32B]10 shows exemplary data collected using the device and data collected using an arterial line, according to various experimental embodiments. [Figure 32C] 10 shows exemplary data collected using the device and data collected using an arterial line, according to various experimental embodiments.

[0057] [Figure 33A] 10 shows exemplary data collected using the device and exemplary data collected using an arterial line, according to various experimental aspects. [Figure 33B] 10 shows exemplary data collected using the device and exemplary data collected using an arterial line, according to various experimental aspects. [Figure 33C] 10 shows exemplary data collected using the device and exemplary data collected using an arterial line, according to various experimental aspects.

[0058] [Figure 34A] 1 shows examples of changes in heart rate and blood pressure as collected using a device and as collected using an arterial line, according to various experimental embodiments. [Figure 34B] 1 shows examples of changes in heart rate and blood pressure as collected using a device and as collected using an arterial line, according to various experimental embodiments. [Figure 34C] 1 shows examples of changes in heart rate and blood pressure as collected using a device and as collected using an arterial line, according to various experimental embodiments.

[0059] [Figure 35] 1 is a graph of systolic blood pressure (sBP) versus arterial sBP calculated from sensor data, according to various experimental embodiments.

[0060] [Figure 36] 1 is a graph of systolic blood pressure (sBP) versus time according to various experimental embodiments.

[0061] [Figure 37] 1 illustrates a method for hemodynamic monitoring in accordance with at least one aspect of the present disclosure.

[0062] [Figure 38A] 1 illustrates a method for measuring and processing one or more physiological parameters in accordance with at least one embodiment of the present disclosure. [Figure 38B] 1 illustrates a method for measuring and processing one or more physiological parameters in accordance with at least one embodiment of the present disclosure. [Figure 38C] 1 illustrates a method for measuring and processing one or more physiological parameters in accordance with at least one embodiment of the present disclosure. [Figure 38D] 1 illustrates a method for measuring and processing one or more physiological parameters in accordance with at least one embodiment of the present disclosure.

[0063] [Figure 39A] 1 illustrates a method for measuring and processing one or more physiological parameters in accordance with at least one embodiment of the present disclosure. [Figure 39B] 1 illustrates a method for measuring and processing one or more physiological parameters in accordance with at least one embodiment of the present disclosure. [Figure 39C] 1 illustrates a method for measuring and processing one or more physiological parameters in accordance with at least one embodiment of the present disclosure.

[0064] While the various aspects discussed herein are susceptible to variations and alternative forms, such aspects have been shown by way of example in the drawings and will be described in detail. However, it should be understood that it is not intended to limit the disclosure to the particular aspects described. Rather, it is intended to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure, including aspects defined in the claims. Furthermore, the term "example" as used throughout this application is merely illustrative and not limiting. DETAILED DESCRIPTION OF THE INVENTION

[0065] Before describing in detail various embodiments of proximity sensor circuits, electrical signal detection circuits, signal processing circuits, and related detection methods, it should be noted that the exemplary embodiments are not limited in application or use to the details of construction, dimensions, and arrangement of parts shown in the accompanying drawings and description. The exemplary embodiments may be implemented or incorporated in other forms, variations, and modifications, and may be practiced or carried out in various ways. Furthermore, unless otherwise indicated, the terms and phrases utilized herein have been chosen for the convenience of the reader and for the purpose of describing the exemplary embodiments, not for purposes of limitation thereof.

[0066] Furthermore, it will be understood that any one or more of the following aspects, expression of aspects, and examples may be combined with any one or more of the other following aspects, expression of aspects, and examples.

[0067] In the following description, by way of non-limiting examples, various implementations and applications are disclosed to provide an understanding of the present disclosure.

[0068] In certain examples, embodiments of the present disclosure include one or more sensor circuits configured and arranged to detect hemodynamic changes (or pulse waveforms) in a user, with the sensor circuit configured in a manner that monitors physiological changes in the user by using a single electrode placed near / on the surface being measured. This and other embodiments employ sensor circuits configured to detect hemodynamic changes in accordance with another of the following embodiments and / or mechanisms.

[0069] A more specific exemplary embodiment is directed to a device having at least one sensor circuit, a sensor circuit including electrodes, and an electrical signal detection circuit. The device can be used to monitor one or more hemodynamic parameters in real time in a noninvasive manner. For example, while the sensor circuit is positioned near or on the skin, the electrical signal detection circuit can detect pulse wave events by monitoring changes in capacitance. The change in capacitance transmitted by the electrodes responds to pressure and / or electric field modulations that may result from pulse wave events or changes in pressure or blood flow within a blood vessel (e.g., hemodynamics). The electrodes can be used to determine changes in capacitance between the electrodes and the user's skin. The sensor circuit including the electrodes can be configured with a conversion circuit that is used to provide an electrical signal to the electrical signal detection circuit that indicates the change in capacitance and / or pressure. A pulse wave event can change the distance between the user's skin and the electrodes and / or the electric field distribution around a blood vessel, resulting in a relative change in the capacitance measured using the sensor circuit. The change in capacitance over time can be processed by an electrical signal sensing circuit and used to generate and / or determine a pulse waveform. In various embodiments, the pulse waveform is correlated to various hemodynamic parameters. As a specific example, the pulse waveform can be processed to determine heart rate, blood pressure, arterial stiffness, and / or blood volume. Machine learning algorithms can be used to derive hemodynamic parameters from the shape of the pulse waveform.

[0070] The electrodes may be in contact with and / or close to the user's skin. In some embodiments, the electrodes are constrained on the user (whether in contact or not) using mechanical restraints (e.g., wristbands, elastic conforming bands, or articles of clothing) and / or adhesives. The electrodes may be placed near blood vessels, preferably near palpable pulse points such as, but not limited to, the radial, brachial, carotid, tibial, dorsal, and temporal pulse points.

[0071] In other specific embodiments, the device includes multiple electrodes. For example, the device may include multiple sensor circuits, each including one of the multiple electrodes. The multiple electrodes may be arranged as part of a conversion circuit that responds to modulation of the distance, pressure, and / or electric field between the user's skin and the electrodes and is used to provide an electrical signal (e.g., digital) to an electrical signal detection circuit that indicates a change in capacitance that may be due to a hemodynamic or pulse wave event. In various related embodiments, the multiple sensor circuits are mechanically separated and / or arranged in an array (e.g., a sensor array). Each of the sensor circuits may be constructed differently, such as to have different geometries, dielectric layers, locations, sensitivities, among other structures as further described herein.

[0072] Various aspects are directed to methods of using the above-described device. The method may include placing at least one electrode of the device near or on a user's skin and detecting a pulse wave event. The pulse wave event may be detected using the device's electrical signal detection circuitry by monitoring changes in capacitance responsive to pressure and / or electric field modulations that may be attributable to hemodynamics or a pulse wave event while the at least one electrode is positioned near or on the user's skin. The pulse wave event may be used to generate a pulse waveform and / or to determine various hemodynamic parameters. For example, the method may include using the pulse wave event to determine diastolic blood pressure, systolic blood pressure, arterial stiffness, and / or blood volume.

[0073] A specific method may include using a flexible or bendable substrate of a wearable device to secure a conversion circuit having at least one sensor circuit. The substrate supports and at least partially surrounds the conversion circuit and the electrical signal detection circuit. The substrate further conforms to a portion of the user, including a blood vessel, and positions at least one electrode sufficiently close to the user's skin to electrically detect hemodynamic or pulse wave events via capacitance changes. The capacitance changes respond to pressure and / or electric field modulations that may result from hemodynamic or pulse wave events. The conversion circuit converts the capacitance changes into an electrical signal. The method further includes detecting hemodynamic or pulse wave events in response to an electrical signal from the conversion circuit via the electrical signal detection circuit, and using communication circuitry within or external to the wearable device to respond to the electrical signal detection circuit by transmitting hemodynamic monitoring data to external circuitry.

[0074] Another aspect is directed to an apparatus for use as part of a wearable device featuring a flexible or bendable substrate that supports and at least partially surrounds a transducer circuit and an electrical signal sensing circuit and is constructed and arranged to conform to a portion of a user including a blood vessel for hemodynamic monitoring. As previously described above, the apparatus includes a transducer circuit having at least one sensor circuit, a sensor circuit including electrodes, an electrical signal sensing circuit, and a communication circuit. Hardware

[0075] Described herein below are various exemplary implementations of proximity sensor circuits and associated sensing methods that use sensor circuits configured and arranged to sense hemodynamic changes (or pulse waveforms) in a user, with the sensor circuit configured in a manner that monitors physiological changes in the user by using one or more electrodes placed near / on the surface being measured.

[0076] 1. Floating foil structure for improved sensitivity

[0077] FIG. 1 illustrates an exemplary proximity sensor 100 having a floating foil structure with a first dielectric layer 102 separating a sensing electrode 104 from an electrically conductive layer 106 in accordance with at least one embodiment of the present disclosure. In various embodiments, the sensing electrode 104 may comprise a plurality of sensing elements or a sensing electrode array. In one embodiment, the first dielectric layer 102 may be made of any suitable polymer or thin dielectric film, including, but not limited to, polyolefin, fluorinated polymer, polyurethane, polyester, silicone, polyamide, polyimide, parylene, and glass. In one embodiment, it is made of polyethylene terephthalate (PET). A second dielectric layer 108 connects the sensing electrode 104 to a housing 110. In the illustrated example, the second dielectric layer 108 is attached to the housing 110 via an adhesive 112. The second dielectric layer 108 may also be made of a suitable polymer, and in the illustrated embodiment, it is made of PET having a thickness of, for example, 150 μm. In one embodiment, the second dielectric layer 108 has a thickness of up to 150 μm, preferably up to 50 μm, and more preferably 1 μm to 25 μm. The housing 110 may be made of low-density polyethylene (LDPE), for example, having a thickness in the range of 100 μm to 300 μm, preferably 200 μm.

[0078] A thin first dielectric layer 102 separates the sensing electrode 104 from the electrically conductive layer 106, which may be ungrounded (not connected to an electronic circuit), grounded, or connected to an antenna to extend the antenna's range. A distance G separates the surface 114 of the sensing electrode 104 from the electrically conductive layer 106. Optimal results are achieved when the first dielectric layer 102 is thick enough to provide some mechanical strength, resilience, and spring force to recover from deformation, e.g., >1 μm, >3 μm, >5 μm, or >10 μm, but thin enough to provide sensitivity, e.g., <25 μm, <50 μm, or <150 μm. If the dielectric constant of the first dielectric layer 102 is sufficiently high, e.g., >5, >10, >50, or >100, the first dielectric layer 102 may be up to 100-300 μm thick. In one embodiment, the first dielectric layer 102 has a thickness of at most 150 μm, preferably at most 50 μm, and more preferably between 1 μm and 25 μm.

[0079] The first dielectric layer 102 can be a polymer film that has been metallized, for example, through a sputtering or other deposition / coating process. Metallized films are particularly advantageous because the electrically conductive layer 106 is thin enough not to significantly affect the mechanical properties of the dielectric polymer film. The electrically conductive layer 106 can comprise a thin metal layer (e.g., aluminum foil, gold foil, copper foil, metal hot or cold transfer film), which can also be used with a dielectric coating on one or both surfaces of the metal layer or on the exposed surface of the sensing electrode 104. Preferably, the dielectric coating of the first dielectric layer 102 is pinhole-free, <1 μm, <3 μm, <5 μm, <10 μm thick, and non-sticky or prone to surface blocking to avoid adhesion to the sensing electrode 104. The surface 114 of the sensing electrode 104 and / or the surface 116 of the first dielectric layer 102, or the coating, can be patterned or textured to reduce surface blocking.

[0080] Aluminum, gold, silver, other metals, carbon, and conductive polymers can be used for the electrically conductive layer 106. The electrically conductive layer 106 and the sensing electrode 104 can also be printed with conductive ink. The thickness of the printed features needs to be controlled to maintain the sensitivity of the proximity sensor 100.

[0081] FIG. 2 illustrates an exemplary proximity sensor 200 having a floating foil structure with a first dielectric layer 218 separating the sensing electrode 204 from the electrically conductive layer 206 to control the distance G (e.g., gap) between the electrically conductive layer 206 and the sensing electrode 204, in accordance with at least one embodiment of the present disclosure. In various embodiments, the sensing electrode 204 may comprise a plurality of sensing elements or a sensing electrode array. In one embodiment, the first dielectric layer 218 may be made of any suitable polymer, and in one embodiment, it is made of PET. The electrically conductive layer 206 may be formed on the surface of the second dielectric layer 202, which is also made of PET, for example. The third dielectric layer 208 connects the sensing electrode 204 to a substrate 220 support material connected to the housing 210 via adhesive 212. The second and third dielectric layers 202, 208 may also be made of a suitable polymer; in the embodiment shown, they are made of PET, with the second dielectric layer 202 having a thickness of, for example, 12 μm and the third dielectric layer 208 having a thickness of, for example, 150 μm. In one embodiment, the second dielectric layer 208 has a thickness of up to 150 μm, preferably up to 50 μm, and more preferably between 1 μm and 25 μm. The housing 210 may be made of LDPE, for example, with a thickness in the range of 100 μm to 300 μm, preferably 200 μm.

[0082] For ease of manufacturing or to ensure that the electrically conductive layer 206 is embedded within the proximity sensor 200 packaged with the housing 210 and is less susceptible to degradation due to exposure to environmental conditions, the distance G between the electrically conductive layer 206 and the sensing electrode 204 can be controlled with a separate dielectric layer, shown herein as the first dielectric layer 218. In one embodiment, the first dielectric layer 218 can be a thin film, or a coated or printed dielectric layer, that covers the surface 214 of the sensing electrode 204. The first dielectric layer 218 should avoid pinholes that could result in shorts between electrodes through multiple connections to the electrically conductive layer 206. Alternatively, the first dielectric layer 218 can be a thicker layer if its dielectric constant is sufficiently high. The first dielectric layer 218 can be floating or bonded to the sensing electrode 204 or to the substrate 220 support material that supports the sensing electrode 204. The first dielectric layer 218 can have a thickness of less than 1 μm, for example. A thin dielectric coating may also be provided on the surface of the electrically conductive layer 206 or on the exposed surface 214 of the sensing electrode 204. Preferably, the first dielectric layer or coating is pinhole-free, <0.1 μm, <1 μm, <3 μm, <5 μm, <10 μm thick, and non-sticky or prone to surface blocking to avoid adhesion to the sensing electrode 204. The surface 214 of the sensing electrode 204 and / or the surface 222 of the first dielectric layer 218, or coating, may be patterned or textured to reduce surface blocking.

[0083] The sensing electrodes 204 may be secured using adhesive or other fastening methods around each electrode element or around the entire electrode array to adhere to the first dielectric layer 218 or foil layer and control the curvature of the gap between the sensing electrodes 204 and the first dielectric layer 218 or foil layer.

[0084] A thin first dielectric layer 218 separates the sensing electrode 204 from the electrically conductive layer 206, which may be ungrounded (not connected to an electronic circuit), grounded, or connected to an antenna to extend the antenna's range. A distance G separates the surface 214 of the sensing electrode 204 from the electrically conductive layer 206. Optimal results are achieved when the first dielectric layer 218 is thick enough to provide mechanical strength, resilience, and spring force for recovery from deformation (e.g., >0.1 μm, >1 μm, >3 μm, >5 μm, or >10 μm), but thin enough to provide sensitivity (e.g., <25 μm, <50 μm, or <150 μm). If the dielectric constant of the first dielectric layer 218 is sufficiently high (e.g., >5, >10, >50, or >100), the first dielectric layer 218 may be up to 100-300 μm thick. In one embodiment, the first dielectric layer 218 has a thickness of up to 150 μm, preferably up to 50 μm, and more preferably between 1 μm and 25 μm.

[0085] The first dielectric layer 218 can be a polymer film that has been metallized, for example, through a sputtering or other deposition / coating process. Metallized films are particularly advantageous because the electrically conductive layer 206 is thin enough not to significantly affect the mechanical properties of the dielectric polymer film. The electrically conductive layer 206 can comprise a thin metal layer (e.g., aluminum foil, gold foil, copper foil, metal hot or cold transfer film), which can also be used with a dielectric coating on one or both surfaces of the metal layer or on the exposed surface of the sensing electrode 204. The dielectric coating of the first dielectric layer 218 is preferably pinhole-free, 0.1 μm, <1 μm, <3 μm, <5 μm, <10 μm thick, and non-sticky or prone to surface blocking to avoid adhesion to the sensing electrode 204. The surface 214 of the sensing electrode 204 and / or the surface 222 of the first dielectric layer 218, or the coating, can be patterned or textured to reduce surface blocking.

[0086] Aluminum, gold, silver, and other metals can be used for the conductive coating of the electrically conductive layer 206. The electrically conductive layer 206 and the sensing electrodes 204 can also be printed with conductive ink. The thickness of the printed features needs to be controlled to maintain the sensitivity of the proximity sensor 200.

[0087] 3 illustrates an exemplary proximity sensor 300 having a floating foil structure with an adhesive layer 324 formed around the periphery of the sensing electrode 304 or around the entire sensing electrode array in accordance with at least one embodiment of the present disclosure. In various embodiments, the sensing electrode 304 may comprise multiple sensing elements or a sensing electrode array. The sensing electrode 304 may be adhesively bonded in some locations, particularly over the sensing electrode lead 326 connecting the sensing electrode 304 to electronics to reduce / control parasitic electronic noise. As shown in FIG. 3 , the adhesive layer 324 is located between the first dielectric layer 302 and the sensing electrode lead 326.

[0088] In various embodiments, the sensing electrode 304 can comprise a plurality of sensing elements or an array of sensing electrodes. In one embodiment, the first dielectric layer 302 can be made of any suitable polymer, and in one embodiment, it is made of PET. The second dielectric layer 308 connects the sensing electrode 304 to the housing 310. In the example shown, the second dielectric layer 308 is attached to the housing 310 via adhesive 312. The second dielectric layer 308 can also be made of a suitable polymer, and in the embodiment shown, it is made of PET having a thickness of, for example, 150 μm. In one embodiment, the second dielectric layer 308 has a thickness of up to 150 μm, preferably up to 50 μm, and more preferably between 1 μm and 25 μm. The housing 310 can be made of LDPE having a thickness in the range of 100 μm to 300 μm, preferably 200 μm.

[0089] A thin first dielectric layer 302 separates the sensing electrode 304 from the electrically conductive layer 306, which may be ungrounded (not connected to an electronic circuit), grounded, or connected to an antenna to extend the antenna's range. A distance G separates the surface 314 of the sensing electrode 304 from the electrically conductive layer 306. Optimal results are achieved when the first dielectric layer 302 is thick enough to provide mechanical strength, resilience, and spring force for recovery from deformation (e.g., >1 μm, >3 μm, >5 μm, >10 μm), but thin enough to provide sensitivity (e.g., <25 μm, <50 μm, <150 μm). If the dielectric constant of the first dielectric layer 302 is sufficiently high (e.g., >5, >10, >50, >100), the first dielectric layer 302 may be up to 100-300 μm thick. In one embodiment, the first dielectric layer 302 has a thickness of at most 150 μm, preferably at most 50 μm, and more preferably between 1 μm and 25 μm.

[0090] The first dielectric layer 302 can be a polymer film that has been metallized, for example, through a sputtering or other deposition / coating process. Metallized films are particularly advantageous because the electrically conductive layer 306 is thin enough not to significantly affect the mechanical properties of the dielectric polymer film. The electrically conductive layer 306 can comprise a thin metal layer (e.g., aluminum foil, gold foil, copper foil, metal hot or cold transfer film), which can also be used with a dielectric coating on one or both surfaces of the metal layer or on the exposed surface of the sensing electrode 304. The dielectric coating of the first dielectric layer 302 is preferably pinhole-free, 0.1 μm, <1 μm, <3 μm, <5 μm, <10 μm thick, and non-sticky or prone to surface blocking to avoid adhesion to the sensing electrode 304. The surface 314 of the sensing electrode 304 and / or the surface 316 of the first dielectric layer 302, or the coating, can be patterned or textured to reduce surface blocking.

[0091] Aluminum, gold, silver, and other metals can be used for the conductive coating of the electrically conductive layer 306. The electrically conductive layer 306 and the sensing electrode 304 can also be printed with conductive ink. The thickness of the printed features needs to be controlled to maintain the sensitivity of the proximity sensor 300.

[0092] 4 illustrates an exemplary proximity sensor 400 having a floating foil structure with an additional layer of material 428 disposed over a sensing electrode lead 426 in accordance with at least one embodiment of the present disclosure. The layer of material 428 can be a dielectric, foam, or double-sided tape. The dielectric, foam, or double-sided tape can also be used over the sensing electrode lead 426 to reduce / control parasitic electronic noise. The additional layer of material 428 should be disposed far enough from the sensing electrode 404 so as not to increase the distance between the sensing element of the sensing electrode 404 and the skin to the extent that the pulse waveform can no longer be detected with sufficient fidelity or signal-to-noise.

[0093] In various embodiments, the sensing electrode 404 can comprise a plurality of sensing elements or an array of sensing electrodes. In one embodiment, the first dielectric layer 402 can be made of any suitable polymer, and in one embodiment, it is made of PET. The second dielectric layer 408 connects the sensing electrode 404 to the housing 410. In the example shown, the second dielectric layer 408 is attached to the housing 410 via adhesive 412. The second dielectric layer 408 can also be made of a suitable polymer, and in the embodiment shown, it is made of PET having a thickness of, for example, 150 μm. In one embodiment, the second dielectric layer 408 has a thickness of up to 150 μm, preferably up to 50 μm, and more preferably between 1 μm and 25 μm. The housing 410 can be made of LDPE having a thickness in the range of 100 μm to 300 μm, preferably 200 μm.

[0094] A thin first dielectric layer 402 separates the sensing electrode 404 from the electrically conductive layer 406, which may be ungrounded (not connected to an electronic circuit), grounded, or connected to an antenna to extend the antenna's range. A distance G separates the surface 414 of the sensing electrode 404 from the electrically conductive layer 406. Optimal results are achieved when the first dielectric layer 402 is thick enough to provide some mechanical strength, resilience, and spring force to recover from deformation, e.g., >1 μm, >3 μm, >5 μm, or >10 μm, but thin enough to provide sensitivity, e.g., <25 μm, <50 μm, or <150 μm. If the dielectric constant of the first dielectric layer 402 is sufficiently high, e.g., >5, >10, >50, or >100, the first dielectric layer 402 may be up to 100-300 μm thick. In one embodiment, the first dielectric layer 402 has a thickness of at most 150 μm, preferably at most 50 μm, and more preferably between 1 μm and 25 μm.

[0095] The first dielectric layer 402 can be a polymer film that has been metallized, for example, through a sputtering or other deposition / coating process. Metallized films are particularly advantageous because the electrically conductive layer 406 is thin enough not to significantly affect the mechanical properties of the dielectric polymer film. The electrically conductive layer 406 can comprise a thin metal layer (e.g., aluminum foil, gold foil, copper foil, metal hot or cold transfer film), which can also be used with a dielectric coating on one or both surfaces of the metal layer or on the exposed surface of the sensing electrode 404. Preferably, the dielectric coating of the dielectric layer 402 is pinhole-free, <1 μm, <3 μm, <5 μm, <10 μm thick, and non-sticky or prone to surface blocking to avoid adhesion to the sensing electrode 404. The surface 414 of the sensing electrode 404 and / or the surface 416 of the first dielectric layer 402, or the coating, can be patterned or textured to reduce surface blocking.

[0096] Aluminum, gold, silver, and other metals can be used for the electrically conductive layer 406. The electrically conductive layer 406 and the sensing electrode 404 can be printed with conductive ink. The thickness of the printed features needs to be controlled to maintain the sensitivity of the proximity sensor 400.

[0097] 2. Reference Sensor

[0098] A reference sensor can be fabricated by modulating the sensitivity of some of the elements of the sensor array. The sensor may not be highly sensitive to changes in the pulse waveform, but may be able to detect changes due to large-scale motion or environmental effects. The signal from the reference sensor can be used to correct the signal from the pulse waveform sensor to correct for baseline changes that may occur due to motion or environmental artifacts.

[0099] One way to create a reference sensor is to change the location or size of the active area of ​​the reference sensor's electrodes relative to the active area of ​​the sensing electrode 404. The reference may be smaller or located farther away from the sensing element to reduce the likelihood that there is sufficient overlap in location with the pulse point to pick up a pulse waveform signal.

[0100] 5 shows an exemplary proximity sensor 500 having a floating foil structure with a reference electrode 530 and a sensing electrode 504 according to at least one embodiment of the present disclosure. The reference sensing electrode 530 may be created by attaching a first dielectric layer 502 having an electrically conductive layer 506 (e.g., foil) to the electrode with a fastening member 532, such as an adhesive, double-sided tape, and / or a dielectric layer, to prevent movement between the reference electrode 530 and the electrically conductive layer 506 and prevent the reference electrode 530 from responding to small changes in position due to skin movement that affects movement of the electrically conductive layer 506 relative to the sensing electrode 504. The reference electrode 530 may detect changes in capacitance due to movement of the entire sensor package or may detect changes in environmental conditions.

[0101] In all cases, the reference electrode 530 must be placed far enough from the sensing electrode 504 so as not to affect the sensitivity of the sensing electrode 504 (through mechanical constraint) or increase the distance between the sensing electrode 504 elements and the skin to the extent that the pulse waveform can no longer be detected with sufficient fidelity or signal-to-noise. The effects of mechanical constraint can be mitigated by mechanically and / or positionally separating the reference electrode 530 elements from the sensing electrode 504 elements, but care must be taken to position them in sufficiently similar locations that they experience the same large-scale motions and environmental conditions.

[0102] The sensing electrode 504 detects both small changes in the pulse waveform as well as larger movement- and environment-induced changes. In various embodiments, the sensing electrode 504 and the reference electrode 530 each comprise multiple sensing elements or a sensing electrode array. In one embodiment, the first dielectric layer 502 can be made of any suitable polymer, and in one embodiment, it is made of PET. The second dielectric layer 508 connects the sensing electrode 504 and the reference electrode 530 to the housing 510. In the example shown, the second dielectric layer 508 is attached to the housing 510 via adhesive 512. The second dielectric layer 508 can also be made of a suitable polymer, and in the embodiment shown, it is made of PET having a thickness of 150 μm. In one embodiment, the second dielectric layer 508 has a thickness of up to 150 μm, preferably up to 50 μm, and more preferably between 1 μm and 25 μm. The housing 510 may be made of LDPE having a thickness of, for example, 100 μm to 300 μm, preferably 200 μm.

[0103] A thin first dielectric layer 502 separates the sensing electrode 504 and reference electrode 530 from the electrically conductive layer 506, and the sensing electrode 504 and reference electrode 530 may be ungrounded (not connected to electronic circuitry), grounded, or connected to an antenna to extend the antenna range. A distance G separates the surface 514 of the sensing electrode 504 from the electrically conductive layer 506. Optimal results are achieved when the first dielectric layer 502 is thick enough to provide some mechanical strength, resilience, and spring force to recover from deformation, e.g., >1 μm, >3 μm, >5 μm, >10 μm, but thin enough to provide sensitivity, e.g., <25 μm, <50 μm, <150 μm. If the dielectric constant of first dielectric layer 502 is sufficiently high, for example, >5, >10, >50, or >100, first dielectric layer 502 may be up to 100-300 μm thick. In one embodiment, first dielectric layer 502 has a thickness of up to 150 μm, preferably up to 50 μm, and more preferably 1 μm-25 μm.

[0104] The first dielectric layer 502 can be a polymer film that has been metallized, for example, through a sputtering or other deposition / coating process. Metallized films are particularly advantageous because the metal coating is thin enough not to significantly affect the mechanical properties of the dielectric polymer film. The electrically conductive layer 506 can comprise a thin metal layer (e.g., aluminum foil, gold foil, copper foil, metal hot or cold transfer film), which can also be used with a dielectric coating on one or both surfaces of the metal layer or on the exposed surface of the sensing electrode 504. The dielectric coating of the first dielectric layer 502 is preferably pinhole-free, <1 μm, <3 μm, <5 μm, <10 μm thick, and non-sticky or prone to surface blocking to avoid adhesion to the sensing electrode 504. The surface 514 of the sensing electrode 504 and / or the surface 516 of the first dielectric layer 502, or the coating, can be patterned or textured to reduce surface blocking.

[0105] Aluminum, gold, silver, and other metals can be used for the electrically conductive layer 506. The electrically conductive layer 506 and the sensing electrode 504 can be printed with conductive ink. The thickness of the printed features needs to be controlled to maintain the sensitivity of the proximity sensor 500.

[0106] 6 illustrates an exemplary proximity sensor 600 having a floating foil structure with a layer 634 of dielectric material attached to or coated onto a reference electrode 630 that is significantly thicker and / or has a significantly lower dielectric constant than the material used in the sensing electrode 604, in accordance with at least one embodiment of the present disclosure. In various embodiments, the layer 634 of dielectric material may be attached to or coated onto a portion of the reference electrode 630 in an electrode array that is significantly thicker and / or has a significantly lower dielectric constant than the material used in the other (sensing) electrodes 604 in the electrode array.

[0107] The sensitivity of single or multiple electrode elements can be modulated in an array of sensing electrodes 604. When multiple reference electrodes 630 are used, they can be tuned to have different sensitivities. When a pair of sensing / reference electrodes 604, 630 are used in differential mode, either one or both of the sensing / reference electrode 604, 630 elements in the pair can be made less sensitive. It can be advantageous to configure the reference electrode 630 and the sensing electrode 604 to have similar overall signal levels, white noise, and / or background signal levels to facilitate subtracting one signal from the other.

[0108] In all cases, the reference electrode 630 needs to be placed far enough from the sensing electrode 604 so as not to affect the sensitivity of the sensing electrode 604 (through mechanical constraint) or increase the distance between the sensing electrode 604 elements and the skin to the extent that the pulse waveform can no longer be detected with sufficient fidelity or signal-to-noise. The effects of mechanical constraint can be mitigated by mechanically and / or positionally isolating the reference electrode 630 elements from the sensing electrode 604 elements, but care must be taken to position them in sufficiently similar locations that they experience the same large-scale motions and environmental conditions. In the case of mechanically isolated sensing elements, a cover film or sealing material 636 can be used to prevent easy fluid ingress.

[0109] The sensing electrode 604 detects both small changes in the pulse waveform as well as larger movement- and environment-induced changes. In various embodiments, the sensing electrode 604 and the reference electrode 630 each comprise multiple sensing elements or an array of sensing electrodes. In one embodiment, the first dielectric layer 602 can be made of any suitable polymer, and in one embodiment, it is made of PET. As shown, the sensing electrode 604 and the reference electrode 630 are mechanically separated such that the sensing electrode 604 is connected to the first housing 610a via the second dielectric layer 608a, and the reference electrode 630 is connected to the second housing 610b via the third dielectric layer 608b. Both the first and second housings 610a, 610b are covered by a cover film or sealing material 636. In the illustrated example, second dielectric layer 608a is attached to first housing 610a via adhesive 612a, and third dielectric layer 608b is attached to second housing 610b via adhesive 612b. Second and third dielectric layers 608a, 608b can also be made of a suitable polymer; in the illustrated embodiment, they are made of PET, each with a thickness of 150 μm. In one embodiment, second and third dielectric layers 608a, 608b each have a thickness of up to 150 μm, preferably up to 50 μm, and more preferably between 1 μm and 25 μm. Housings 610a, 610b can be made of LDPE, each with a thickness of 100 μm to 300 μm, preferably 200 μm.

[0110] A thin first dielectric layer 602 separates the sensing electrode 604 and reference electrode 630 from the electrically conductive layer 606, and the sensing electrode 604 and reference electrode 630 may be ungrounded (not connected to electronic circuitry), grounded, or connected to an antenna to extend the antenna range. A distance G separates the surface 614 of the sensing electrode 604 from the electrically conductive layer 606. Optimal results are achieved when the first dielectric layer 602 is thick enough to provide some mechanical strength, resilience, and spring force to recover from deformation, e.g., >1 μm, >3 μm, >5 μm, >10 μm, but thin enough to provide sensitivity, e.g., <25 μm, <50 μm, <150 μm. If the dielectric constant of first dielectric layer 602 is sufficiently high, for example, >5, >10, >50, or >100, first dielectric layer 602 may be up to 100-300 μm thick. In one embodiment, first dielectric layer 602 has a thickness of up to 150 μm, preferably up to 50 μm, and more preferably 1 μm-25 μm.

[0111] The first dielectric layer 602 can be a polymer film that has been metallized, for example, through a sputtering or other deposition / coating process. Metallized films are particularly advantageous because the electrically conductive layer 606 is thin enough not to significantly affect the mechanical properties of the dielectric polymer film. The electrically conductive layer 606 can comprise a thin metal layer (e.g., aluminum foil, gold foil, copper foil, metal hot or cold transfer film), which can also be used with a dielectric coating on one or both surfaces of the metal layer or on the exposed surface of the sensing electrode 604. The dielectric coating of the dielectric layer 602 is preferably pinhole-free, <1 μm, <3 μm, <5 μm, <10 μm thick, and non-sticky or prone to surface blocking to avoid adhesion to the sensing electrode 604. The surface 614 of the sensing electrode 604 and / or the surface 616 of the first dielectric layer 602, or the coating, can be patterned or textured to reduce surface blocking.

[0112] Aluminum, gold, silver, and other metals can be used for the electrically conductive layer 606. The electrically conductive layer 606 and the sensing electrode 604 can be printed with conductive ink. The thickness of the printed features needs to be controlled to maintain the sensitivity of the proximity sensor 600.

[0113] 3. Foam layer for improved adaptability

[0114] 7 illustrates an exemplary proximity sensor 700 having a floating foil structure with a foam layer 738 disposed between the sensor elements (e.g., the sensing electrode 704 and the reference electrode 730) and an attachment structure 740, such as a wristband, to provide conformance and ensure that both the reference electrode 730 and the sensing electrode 704 have similar contact with the skin, in accordance with at least one embodiment of the present disclosure. The foam layer 738 between the sensing and reference electrode elements 704, 730 and the attachment structure 740, such as a wristband, may be used to provide conformance and ensure that both the sensing and reference electrode elements 704, 730 have similar contact with the skin. As shown, the sensing and reference electrode elements 704, 730 may optionally be mechanically separated such that the sensing electrode 704 is connected to the first housing 710a via a second dielectric layer 708a and the reference electrode 730 is connected to the second housing 710b via a third dielectric layer 708b.

[0115] The band (or mounting structure 740) itself can be a foam such as EVA craft foam, clean wipe foam, or medical-grade foam (e.g., 3M9776, 3M1772, or Rosidal 77362). It is advantageous to use a small-cell, open-cell foam that is compressible, breathable, and / or stretchable, yet provides sufficient mechanical integrity to serve as a support material for the sensing and reference electrode 704, 730 arrays and different fastening mechanisms, such as hook-and-loop materials, eyelet and buckle fastenings, cam buckles, and adhesives. Materials for the foam layer 738 with lower mechanical integrity can be supported by lamination to another material, such as the loop fabric used for the hook-and-loop fastening members. The foam layer 738 and / or additional laminate materials can be perforated in some sections to increase stretch and breathability. The use of one or more regions / layers of viscoelastic or dissipative materials that can partially or entirely absorb the effects of mechanical stimuli within different frequency ranges may be desirable to help mitigate signal artifacts resulting from different types of movement, vibration, or environmental effects. Such dissipative material may be incorporated into the device's mounting structure 740 or may be used as an accessory to partially isolate the patient's limbs or body from the environment.

[0116] In all cases, the reference electrode 730 needs to be placed far enough from the sensing electrode 704 so as not to affect the sensitivity of the sensing electrode 704 (through mechanical constraint) or increase the distance between the sensing electrode 704 elements and the skin to the extent that the pulse waveform can no longer be detected with sufficient fidelity or signal-to-noise. The effects of mechanical constraint can be mitigated by mechanically and / or positionally isolating the reference electrode 730 elements from the sensing electrode 704 elements, but care must be taken to position them in sufficiently similar locations that they experience the same large-scale motions and environmental conditions. In the case of mechanically isolated sensing elements, a cover film or sealing material can be used to prevent easy ingress of fluids.

[0117] The sensing electrode 704 detects both small changes in the pulse waveform as well as larger movement- and environment-induced changes. In various embodiments, the sensing electrode 704 and the reference electrode 730 may each comprise multiple sensing elements or a sensing electrode array. In one embodiment, the first dielectric layer 702 may be made of any suitable polymer, and in one embodiment, it is made of PET. As shown, the sensing electrode 704 and the reference electrode 730 are mechanically separated such that the sensing electrode 704 is connected to the first housing 710a via the second dielectric layer 708a, and the reference electrode 730 is connected to the second housing 710b via the third dielectric layer 708b. In the illustrated example, the second dielectric layer 708a is attached to the first housing 710a via adhesive 712a, and the third dielectric layer 708b is attached to the second housing 710b via adhesive 712b. The second and third dielectric layers 708a, 708b may also be made of a suitable polymer, and in the embodiment shown, are made of PET, each having a thickness of 150 μm. In one embodiment, the second and third dielectric layers 708a, 708b each have a thickness of up to 150 μm, preferably up to 50 μm, and more preferably between 1 μm and 25 μm. The housings 710a, 710b may be made of LDPE, each having a thickness of 100 μm to 300 μm, preferably 200 μm.

[0118] A thin first dielectric layer 702 separates the sensing electrode 704 and reference electrode 730 from the electrically conductive layer 706, and the sensing electrode 704 and reference electrode 730 may be ungrounded (not connected to electronic circuitry), grounded, or connected to an antenna to extend the antenna range. A distance G separates the surface 714 of the sensing electrode 704 from the electrically conductive layer 706. Optimal results are achieved when the first dielectric layer 702 is thick enough to provide some mechanical strength, resilience, and spring force to recover from deformation, e.g., >1 μm, >3 μm, >5 μm, >10 μm, but thin enough to provide sensitivity, e.g., <25 μm, <50 μm, <150 μm. If the dielectric constant of the first dielectric layer 702 is sufficiently high, for example, >5, >10, >50, or >100, the first dielectric layer 702 may be up to 100-300 μm thick. In one embodiment, the first dielectric layer 702 has a thickness of up to 150 μm, preferably up to 50 μm, and more preferably 1 μm-25 μm.

[0119] The first dielectric layer 702 can be a polymer film that has been metallized, for example, through a sputtering or other deposition / coating process. Metallized films are particularly advantageous because the electrically conductive layer 706 is thin enough not to significantly affect the mechanical properties of the dielectric polymer film. The electrically conductive layer 706 can comprise a thin metal layer (e.g., aluminum foil, gold foil, copper foil, metal hot or cold transfer film), which can also be used with a dielectric coating on one or both surfaces of the metal layer or on the exposed surface of the sensing electrode 704. Preferably, the dielectric coating of the dielectric layer 702 is pinhole-free, <1 μm, <3 μm, <5 μm, <10 μm thick, and non-sticky or prone to surface blocking to avoid adhesion to the sensing electrode 704. The surface 714 of the sensing electrode 704 and / or the surface 716 of the first dielectric layer 702, or the coating, can be patterned or textured to reduce surface blocking.

[0120] Aluminum, gold, silver, and other metals can be used for the electrically conductive layer 706. The electrically conductive layer 706 and the sensing electrode 704 can be printed with conductive ink. The thickness of the printed features needs to be controlled to maintain the sensitivity of the proximity sensor 700.

[0121] 8 illustrates an exemplary proximity sensor 800 having a floating foil structure with a reference electrode 830 disposed on the opposite side of the substrate layer 838 from the sensing electrode 804, in accordance with at least one embodiment of the present disclosure. In some cases, it may be advantageous to position the reference electrode 830 on the opposite side of the substrate layer 838 from the sensing electrode 804. This allows the reference electrode 830 sensor to experience movement similar to the sensing electrode 804 sensor, but with significantly lower exposure to pulse signals. The substrate layer 838 may be made of any material, including, but not limited to, foam, cloth, dielectric material, conductive material, leather, plastic, and combinations of such materials.

[0122] The sensing electrode 804 is disposed on one side of the substrate layer 838 and is separated from the electrically conductive layer 806 of the first dielectric layer 802 by a second dielectric layer 818. A sealing layer 836 (e.g., Tegaderm) covers the first dielectric layer 802 on the side opposite the electrically conductive layer 806.

[0123] The reference electrode 830 is disposed on the other side of the substrate layer 838 and is separated from the electrically conductive layer 846 of the third dielectric layer 848 by a fourth dielectric layer 844. The reference electrode 830 sensor stack is embedded within the mounting structure 840.

[0124] The band (or mounting structure 840) itself can be a foam such as EVA craft foam, clean wipe foam, or medical-grade foam (e.g., 3M9776, 3M1772, or Rosidal 77362). It is advantageous to use a small-cell, open-cell foam that is compressible, breathable, and / or stretchable, yet provides sufficient mechanical integrity to serve as a support material for the sensing and reference electrode 804, 830 arrays and different fastening mechanisms, such as hook-and-loop materials, eyelet and buckle fastenings, cam buckles, and adhesives. Materials for the substrate layer 838 that offer less mechanical integrity can be supported by lamination to another material, such as the loop fabric used for the hook-and-loop fastening members. The substrate layer 838 and / or additional laminate material may be perforated in some sections to increase stretch and breathability. To help mitigate signal artifacts resulting from different types of movement, vibration, or environmental effects, it may be desirable to use one or more regions / layers of viscoelastic or dissipative material that can partially or fully absorb the effects of mechanical stimuli within different frequency ranges. Such dissipative material may be incorporated into the device's mounting structure 840 or may be used as an accessory to partially isolate the patient's limbs or body from the environment.

[0125] In all cases, the reference electrode 830 needs to be placed far enough from the sensing electrode 804 so as not to affect the sensitivity of the sensing electrode 804 (through mechanical constraint) or increase the distance between the sensing electrode 804 elements and the skin to the extent that the pulse waveform can no longer be detected with sufficient fidelity or signal-to-noise. The effects of mechanical constraint can be mitigated by mechanically and / or positionally isolating the reference electrode 830 elements from the sensing electrode 804 elements, but care must be taken to position them in sufficiently similar locations that they experience the same large-scale motions and environmental conditions. In the case of mechanically isolated sensing elements, a cover film or sealing material 836 can be used to prevent easy ingress of fluids.

[0126] The sensing electrode 804 detects both small changes due to the pulse waveform as well as larger movement- and environment-induced changes. In various embodiments, the sensing electrode 804 and the reference electrode 830 may each comprise a plurality of sensing elements or a sensing electrode array. In one embodiment, the first and third dielectric layers 802, 848 may be made of any suitable polymer, and in one embodiment, they are made of PET. The second and fourth dielectric layers 818, 844 may also be made of a suitable polymer, and in the illustrated embodiment, are made of PET, each having a thickness of, for example, 150 μm.

[0127] Thin first and third dielectric layers 802, 848 separate the sensing electrode 804 and reference electrode 830 from their respective electrically conductive layers 806, 846, which may be ungrounded (not connected to electronic circuitry), grounded, or connected to an antenna to extend the antenna range. A distance G1 separates the surface 814 of the sensing electrode 804 from the electrically conductive layer 806. A distance G2 separates the surface 842 of the reference electrode 830 from the electrically conductive layer 846. Optimal results are achieved when the first and third dielectric layers 802, 848 are thick enough to provide some mechanical strength, resilience, and spring force to recover from deformation, e.g., >1 μm, >3 μm, >5 μm, >10 μm, but thin enough to provide sensitivity, e.g., <25 μm, <50 μm, <150 μm. If the dielectric constant of the first and third dielectric layers 802, 848 is sufficiently high, e.g., >5, >10, >50, or >100, the first and third dielectric layers 802, 848 may be up to 100-300 μm thick. In one embodiment, the first and third dielectric layers 802, 846 may each have a thickness of up to 150 μm, preferably up to 50 μm, and more preferably 1 μm-25 μm.

[0128] The first and third dielectric layers 802, 848 can be made of polymer films that have been metalized, for example, through sputtering or other deposition / coating processes. Metallized films are particularly advantageous because the electrically conductive layers 806, 846 are thin enough not to significantly affect the mechanical properties of the dielectric polymer film. The electrically conductive layers 806, 846 can comprise thin metal layers (e.g., aluminum foil, gold foil, copper foil, metal hot or cold transfer films), which can also be used with a dielectric coating on one or both surfaces of the metal layer or on the exposed surfaces of the sensing or reference electrodes 804, 830. It is preferred that the dielectric coating of the dielectric layer 702 be pinhole-free, <1 μm, <3 μm, <5 μm, or <10 μm thick, and non-sticky or prone to surface blocking to avoid adhesion to the sensing or reference electrodes 804, 830. The surfaces 814, 842 of the sensing and reference electrodes 804, 830 and / or the surfaces 816, 850 of the second and fourth dielectric layers 818, 844, or coatings, may be patterned or textured to reduce surface blocking.

[0129] Aluminum, gold, silver, and other metals can be used for the conductive coating of the electrically conductive layers 806, 846. The conductive coating of the electrically conductive layers 806, 846 and the sensing or reference electrodes 804, 830 can be printed with conductive ink. The thickness of the printed features needs to be controlled to maintain the sensitivity of the proximity sensor 800.

[0130] 4. Material Selection

[0131] Sensor Attachment: A number of materials may be used to secure the sensor array of proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, 1300 shown in Figures 1-8, 12, 13, 15, and 16 to the skin as bands, patches, or other methods. Materials may be flexible, thin, slightly elastic or stretchable, and optionally somewhat breathable (semi-permeable or semi-occlusive), and water-resistant for comfort and ease of use. Some preferred materials include self-adhesive bandage materials (e.g., 3M Corban), medical tape (e.g., 3M Microfoam Surgical Tape), kinesiology tape (e.g., Locktape or Theraband), EVA foam, clean wipe foam (e.g., Foamtec Clean Wipes), foams such as those used for infant ID bands (e.g., PDC Precision Newborn Bands or GBS EasyID Bands), medical foam (e.g., 3M9776), silicone, polyurethane, styrene copolymers, acrylic copolymers, fluorinated copolymers, polyolefins, ethylene vinyl acetate, neoprene, PVC, and similar thermoplastic and thermoset elastomers. Materials can be solid materials or foams, or woven or nonwoven fabrics, with or without texture and / or cutouts or perforations for stretch or breathability, or combinations thereof (e.g., laminated or with glued / connected / sewn sections) (e.g., Gore-Tex fabric, Nexcare bandages, Tegaderm dressings, Glad Press'n Seal Wrap). To secure the band around a body part or on the skin, the material may be self-adhesive or may have a sticky active surface, or may use sections with hook and loop materials (e.g., Velcro®), adhesives (including silicone, acrylate, polyurethane), watch band type buckles or clasps.To minimize movement of the sensor array relative to the skin, materials with sticky surfaces (e.g., silicone or Fabrifoam), adhesive-backed materials such as kinesiology tape (e.g., Locktape or Kinesiology Tape), or nanostructured dry adhesive surfaces (e.g., Setex) can be used. Commercially available watch bands made of metal, leather, silicone, polyurethane, and other polymeric materials have also been used for longer-term use. Latex-free and nickel-free materials are preferred to avoid allergic reactions or skin irritation.

[0132] 9 illustrates one diagram of an example mounting structure 900 for a proximity sensor having a floating foil structure, such as proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, 1300, as shown in FIGS. 1-8, 12, 13, 15, and 16, where the mounting structure includes a band, patch, or multiple materials used in other ways to secure the sensor array to the skin, in accordance with at least one aspect of the present disclosure.

[0133] FIG. 10 illustrates a cross-sectional view of the exemplary mounting structure 900 shown in FIG. 9 taken along section line 10-10, in accordance with at least one aspect of the present disclosure.

[0134] FIG. 11 illustrates a detailed view of a cross-sectional view of the exemplary mounting structure 900 shown in FIG. 10 taken along line 11, in accordance with at least one aspect of the present disclosure.

[0135] 9-11, the sensor assembly may include layers of material that can be laminated together, for example, as die-cut stickers, prior to assembly of the band to simplify the manufacturing process. To create this sticker, it may be advantageous to use island-like stacks of patches of different materials, where adhesive is applied only to the periphery of the patch, allowing some or all of the material in the center of the patch to move independently. The mounting structure 900 includes three materials 902-906, an adhesive side 908, and a metalized side 910.

[0136] In one example, the first material 902 can be a <5 μm thick PET film, the second material 904 can be a ∼12 μm thick PET film metallized with aluminum on the metallized side 910, and the third material 906 can be a ∼25 μm total thickness polyurethane film with an adhesive on one adhesive side 908. A patch of the second material 904 can be adhered to a patch of the third material 906. A larger patch of the first material 902 can then be laminated to the composite of the second and third materials 904, 906 such that it is adhered to the periphery of the patch of the second material 904 as shown in FIGS.

[0137] In another example, adhesive may be printed on the adhesive side 908 as a pattern that defines the perimeter of the patch area on the second material 904. The first material 902 is then laminated onto the second material 904. The composite of the first and second materials 902, 904 is then die cut, laser cut, or otherwise singulated so that it may then be laminated onto the third material 906 in the form of islands.

[0138] An exemplary assembly process may include: (1) making a slit in a band made of laminated medical foam and loop material, or a pre-made identification band such as a PDC or GBS band, and inserting a sensor flex circuit for the sensor array through the slit. The sensor flex circuit is optionally glued to the band; (2) using a sticker to hold and seal the sensor flex circuit in place; and (3) connecting the electronics to the flex circuit.

[0139] The electronics or sensor packaging for proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 shown in Figures 1-8, 12, 13, 15, and 16 can comprise a film with an adhesive or blocking (self-adhesive) surface (e.g., polyolefin packing tape, Tegaderm dressing, GladPress Seal Wrap, silicone, or polyurethane film) that can also be used as disposable packaging for reusable electronics or sensor elements. The material can be wrapped around the electronics, battery / power source, and / or sensor array and attached to a band or patch with adhesive, double-sided tape or hook-and-loop material, snaps, or other low-cost, low-profile attachment methods.

[0140] Alternatively, a molded case or clamshell housing may be employed, which may be press-fit closed or reversibly sealed with a snap fit. Suitable materials for these include silicone, polyurethane, polyolefin, acrylate, polyester, PETG, EVA, and copolymers, as well as blends of such materials. Vacuum or thermoforming, injection molding, rotational molding, blow molding, or reaction injection molding may be used to manufacture the housing.

[0141] Reengageable contacts may be provided between the electronic module and the sensor / electrode leads. In one aspect, printed conductive elastomeric bumps may be provided for resiliently compressible reengageable contacts.

[0142] In one embodiment, some or all of the electronics and / or battery / power supply for the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 shown in Figures 1-8, 12, 13, 15, and 16 are packaged in a module or "pebble" separate from the sensor array. The electronics module may be encapsulated or sealed. To establish electrical contact between the sensor array and the electronics module and / or battery / power supply, it may be advantageous to use a structure for electrically connecting components that is easy to use and low-cost. One such method involves printing, stenciling, or molding elastomeric connection points onto the leads of the sensor array. The material may be an elastomeric conductive polymer compound or a carbon- or metal-filled polymer composite, e.g., a conductive ink used in polymer solder bumps. It may be advantageous to use a thixotropic material that can be rapidly cured to produce tall structures, preferably >0.25 mm, >0.5 mm, or >1 mm in height. 3-D or aerosol jet printers can also be used to produce tall structures. Materials that are somewhat conformable, elastomeric, and do not exhibit significant compression set are preferred to allow some deformation when a small amount of compressive force is applied to contact the conductive pads on the electronic module with the conductive bumps on the sensor electrode leads. One such material is ThreeBond TB3333E silver-filled silicone, which can be dispensed with an air-driven adhesive or solder paste dispenser.

[0143] 12 illustrates an exemplary proximity sensor 1000 including a re-engageable contact 1002 between an electronics module 1004 and a sensor / electrode lead 1006 having a printed conductive elastomeric conductive bump 1014 to form a resiliently compressible re-engageable contact 1002 in accordance with at least one embodiment of the present disclosure. The proximity sensor 1000 may represent any one of the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 depicted in FIGS. 1-8, 12, 13, 15, and 16. The re-engageable contact 1002 electrically connects the sensor / electrode lead 1006 on a sensor element substrate 1008 supporting the proximity sensor 1000 to a conductive pad 1010 disposed on the electronics module 1004. In one embodiment, the elastomeric conductive bumps 1014 of the re-engageable contacts 1002 are formed from a thixotropic elastomeric conductive ink according to the process description below in conjunction with FIG.

[0144] FIG. 13 illustrates an exemplary method 1100 for printing the conductive elastomeric bumps 1002 shown in FIGS. 12, 14, and 15 for resiliently compressible reengageable contacts according to at least one embodiment of the present disclosure. With reference to FIGS. 12 and 13, the method 1100 includes printing 1102 conductive ink 1014 for sensor element electrodes, leads 1006, and connection points on a substrate 1008. Optionally, the method 1100 includes embossing 1104 the connection points. The method 1100 includes printing 1106 conductive ink 1014 over the embossed connection points. For a reusable electronic module 1004, it is desirable for the conductive pads 1010 to be sealed to the surface of the electronic module 1004 to facilitate cleaning after each use.

[0145] Referring also to FIG. 12, FIG. 14 illustrates an example of a conductive elastomeric bump 1002 printed on an electrode lead 1006 that is pressed against an electronic module 1004, in accordance with at least one aspect of the present disclosure.

[0146] Referring to Figures 12-14, features such as bosses on the tray or clamshell may be used to provide sufficient pressure to deform elastomeric conductive bumps 1002 with conductive pads 1010 on the electronic module 1004 and achieve electrical contact between the sensor element substrate 1008 and the electronic module 1004, thereby holding the electronic module 1004 or printed circuit board in place.

[0147] 12-14, in one embodiment, the conductive elastomeric bumps 1002 may alternatively be printed with conductive ink 1014 on the electronic module 1004 and pressed against the electrode leads 1006. This may be less suitable for applications where reusable electronics need to be bonded to the electrode leads 1006 multiple times, as the conductive elastomeric bumps 1002 may not be robust enough for multiple uses.

[0148] 15 illustrates an exemplary proximity sensor 1200 including conductive elastomeric bumps 1202 fabricated by embossing structures 1214 into a sensor element substrate 1208 that supports the sensing / reference electrodes of the proximity sensor 1200, in accordance with at least one embodiment of the present disclosure. The proximity sensor 1200 is representative of the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 illustrated in FIGS. 1-8, 12, 13, 15, and 16. The conductive bumps 1202 may also be fabricated by embossing structures 1214 into the sensor element substrate 1208 that supports the electrodes, as described in connection with FIG. 13.

[0149] 13 and 15 , the electrode leads 1206 are disposed on the embossed structures 1214 and then overprinted with conductive ink 1014. The electrode leads 1206 may optionally be formed on the sensor element substrate 1208 before embossing 1104 the connection points. To minimize loss of conductivity in the electrode leads 1206, it may be advantageous to emboss 1104 the region around the area of ​​the electrode leads 1206 (i.e., emboss a flat plateau around the electrode leads 1206). In the event that it is necessary to emboss 1104 the conductive material forming the electrode leads 1206, it may be advantageous to minimize the slope of the embossed structures 1212 to minimize loss of conductivity in the electrode leads 1206. For example, while it is possible to provide steep walls along the sides of the electrode lead 1206, it is best to provide a gradual slope in the deformed area of ​​the embossed structure 1212 when embossing 1104 the entire electrode lead 1206. The conductive elastomeric bumps 1202 make electrical contact with conductive pads 1210 disposed on the electronic module 1204.

[0150] FIG. 16 illustrates a partial view of an example proximity sensor 1300 including conductive features 1302 fabricated by mechanically deforming an electrical lead 1306 in accordance with at least one embodiment of the present disclosure. The mechanically deformed electrode lead 1306 is disposed on a sensor element substrate 1308. The proximity sensor 1300 may represent any one of the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 depicted in FIGS. 1-8, 12, 13, 15, and 16. Another method for providing a low-cost connection between the electronics module 1304 and the sensor array of the proximity sensor 1300 includes mechanically deforming the electrical lead 1306 by supporting it with a compliant spacer 1316, such as a molded elastomer section or piece of foam. The compliant spacers 1316 are optionally shaped to optimize the curvature of the deformed electrode leads 1306 to control the contact area between the electrode leads 1306 and the conductive pads 1310 on the electronics module 1304. Additionally, providing a support frame such as the compliant spacers 1316 around the contact points formed by the conductive features 1302 may also improve assistance in controlling the contact area.

[0151] 17 illustrates an exemplary method 1400 for forming connections between an electronics module 1304 and a sensor array by mechanically deforming electrical leads 1306 as shown in FIG. 16 , according to at least one embodiment of the present disclosure. Referring now to FIGS. 16 and 17 , in one embodiment, method 1400 includes printing 1402 conductive ink for sensor element electrodes, leads 1306, and connection points. Optionally, method 1400 includes shaping 1404 an area having the connection points. Also, optionally, method 1400 includes mechanically isolating 1406 the connection points. Method 1400 further includes supporting 1408 the connection points with a molded / conformable or foam substrate, such as a compliant spacer 1316.

[0152] 18 illustrates an exemplary connector 1500 formed by the method 1400 of FIG. 17 having improved compatibility and mechanically separated individual electrode leads 1502 in an array 1504 of electrode leads, in accordance with at least one embodiment of the present disclosure. This configuration may improve compatibility and mechanically separate the individual electrode leads 1502 within the array of electrode leads.

[0153] 19 illustrates an example connector 1600 formed by the method of FIG. 17 having mechanically rigid spring fingers 1602 supported and deformed with foam or other spacer material 1604 in accordance with at least one embodiment of the present disclosure. The additional mechanically rigid spring fingers 1602 may be used in place of more compliant electrodes, optionally supported and / or deformed with foam or other spacer material 1604. The connectors 1500, 1600 may be insert molded, press-fit, or otherwise incorporated into a bezel or container to hold the electronic device in place.

[0154] 20 illustrates an exemplary electronic module 1700 having mating contacts 1702 formed on a housing 1704 of the electronic module 1702 for use with the connector 1600 shown in FIG. 19, in accordance with at least one embodiment of the present disclosure. In an alternative embodiment, spring fingers 1602 may be employed on the electronic module 1702 that press against the electrode lead wires. System Configuration

[0155] The attachment structures 740, 840 shown in Figures 7 and 8 may each be implemented in the form of a band, patch, or other suitable structure. Bands may be adjustable in size to fit radial, brachial, tibial, dorsal, and / or femoral pulse points. Patches may be applied to other pulse points where applying a band may be difficult, such as the carotid artery, temporal region, on the hand or finger, or behind the ear. Band and patch materials may be somewhat stretchable using materials such as self-adhesive bandages (e.g., 3M Corban), EVA, silicone, polyurethane, styrene copolymers, olefin copolymers, stretchable hook-and-loop materials (e.g., 3M Velstrap), foam, dressing materials (e.g., 3M Tegaderm), and fabric. Sensors may also be incorporated into bands made of less stretchable materials such as leather, vinyl, metal mesh, nylon mesh, fabric, hook-and-loop straps (e.g., 3M Velcro), and other typical watch band materials. Bands may be fastened with hook-and-loop closures, buckles, snaps, magnets, and other fastening methods often used with watch bands.

[0156] Sensor elements comprising sensing electrodes 114, 214, 314, 414, 514, 614, 714, 814 shown in FIGS. 1-8 and / or reference electrodes 530, 630, 730, 830 shown in FIGS. 5-8 may be positioned on a mounting structure 740, 840, such as a band and / or patch, so that they may be positioned near pulse points. Arrays of sensor elements may be used to provide a level of positional tolerance for ease of use. Sensor elements may be arranged in a fan-out configuration to improve positional tolerance relative to the pulse points. It may be advantageous to distribute sensor elements along the length of the band to simultaneously pick up multiple pulse points, such as dorsal and tibial locations or radial and ulnar locations. Sensor elements may be positioned individually or in pairs. They may operate singly or in differential mode, subtracting one from the other for baseline correction, or as two legs of an LC tank circuit (e.g., in the manner of the TI FDC2214) for better sensitivity and noise rejection.

[0157] The sensor elements may have dimensions with an aspect ratio >1, with the long axis oriented parallel to the artery for better connection and higher signal, or perpendicular to the artery for better positional tolerance. Lengths of 5-30 mm and widths of 0.25 mm-2 mm may be advantageous to balance positional tolerance and signal quality. Different elements or pairs of elements may have different orientations. It may be advantageous for the distance between pairs of sensor elements to be minimized to the limits of the manufacturing process, and inter-element distances of less than 0.5 mm may be advantageous to improve signal quality in differential modes. Sensing and / or reference electrodes for the sensor elements may be deployed with connections to the electronics for easier alignment.

[0158] FIG. 21 illustrates an exemplary sensor band 1800 including a band 1852 and an electronic module 1856 in accordance with at least one embodiment of the present disclosure. The band 1852 is configured for an adult with an adjustable size to fit radial, humeral, tibial, dorsal, and / or femoral pulse points. The band 1852 may be adjustably secured to an adult using a low-profile hook 1866 fastening member secured to a low-profile loop fabric 1868. The electronic module 1856 ("pebble") is sealed or partially sealed and includes an electronic circuit 1854 electrically connected to a battery 1872 and one or more proximity sensors disposed on the opposite side of the band 1852. In one embodiment, the electronic circuit 1854 and battery 1872 may be reusable, while the proximity sensors and band 1852 are disposable. The reusable electronic circuit 1854 and disposable proximity sensor 1872 snap-fit ​​into the tray 1858 and cover 1864 housing. The electronic module 1856 is received within a shell 1870 that is secured to the band 1852 via known fastening methods. The reusable electronic circuit 1854 and battery 1872 snap-fit ​​within the tray 1858 and cover 1864. The surface design of the electronic module 1856 ("pebble") may be substantially smooth to facilitate cleaning with antibacterial wipes. The proximity sensor on the band 1852 may be configured as any one or more of the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 described in FIGS. 1-8, 12, 13, 15, and 16.

[0159] Encapsulation can be achieved through overmolding, insert molding, potting, or casting. Materials for the tray 1808 include silicone, polyurethane, styrene copolymer, olefin copolymer, ABS, PET, polyolefin, nylon, polycarbonate, and PETG. The multi-part case of the electronics module 1856 can be assembled around the reusable electronic circuit 1854 and disposable proximity sensor 1872 and secured to the cover 1864 via fasteners 1862, such as a snap fit, adhesive, heat welding, or other known fastening methods.

[0160] Conductive leads or vias may be incorporated into the shell 1860 (e.g., through insert molding) to make connections to the sensor electrodes. Alternatively, the sensor electrode leads may be fed into the shell 1860 through slots in the sidewalls or through the bottom of the shell 1860, with alignment facilitated by molded features in the shell 1860. Magnets may be used to aid alignment and secure the connection between the shell 1860 and the electronics module 1856 ("pebble"). A schematic cross-sectional view of a proximity sensor 1800 with a band 1852 configured for an adult is described below in connection with FIG. 22.

[0161] FIG. 22 illustrates a schematic cross-sectional view of a sensor band 1800 including an adult-sized band 1852 and an electronic module 1856, as shown in FIG. 21 , in accordance with at least one embodiment of the present disclosure. As described in connection with FIG. 21 , the band 1852 is configured in an adult size. Now, referring to both FIGS. 21 and 22 , the sensor band 1800 includes a disposable proximity sensor 1872 secured to the band 1852 and covered by a sealing layer 1836. The sealing layer 1836 includes an adhesive 1837 for attaching to the band 1852 and the first dielectric layer 1802. The band 1852 may be formed of a lightweight, self-adhesive rubber that provides controlled, consistent compression and conforms to all body contours. A longitudinally oriented laminate of nonwoven material and elastic fibers provides excellent elasticity. The band 1852 material adheres to itself without the use of pins, clips, or tape. In one embodiment, band 1852 may be made from a material known in the industry as Corban.

[0162] The disposable proximity sensor 1872 includes a first dielectric layer 1802 having an electrically conductive layer 1806 connected to a sensing electrode 1804. The sensing electrode 1804 is secured to the band 1852 by a pressure-sensitive adhesive 1874 (PSA) and is electrically connected to conductive bumps 1876 disposed on a shell 1860 configured to receive an electronics module 1856. The sensing electrode 1804 is electrically connected to the conductive bumps 1876 by a connector, shown in FIG. 22 as a flexible flat cable 1826 (FFC), which extends from the disposable proximity sensor 1872 to the shell 1860 for electrically connecting to the electronics module 1856. The second dielectric layer 1806 is disposed between the sensing electrode 1804 and the first dielectric layer 1802. A third dielectric layer 1808 having an adhesive is attached to the FFC 1826 on one side and to the band 1852 on the other side by another adhesive layer 1812. Thus, the sensing electrode 1804 is electrically connected to the electronic module 1856 .

[0163] In one embodiment, sealing layer 1836 can be a 25 μm polyurethane layer with adhesive layer 1837 known in the industry as Tegaderm. In one embodiment, first dielectric layer 1802 can be a 12 μm PET layer with an aluminum (AL) electrically conductive layer 1806. In one embodiment, second dielectric layer 1806 can be 2.5 μm PET. In one embodiment, third dielectric layer 1808 can be 25 μm polypropylene with an acrylic adhesive. Adhesive layer 1812 is a 12 μm ultra-thin acrylic transfer tape. In one embodiment, band 1852 is ~9 inches in length, which is sized for an adult wearer. Notwithstanding the example dimensions provided in this section, the dimensions of the various dielectric layers of the proximity sensor 1872 may be selected according to the dimensions described herein in connection with proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, 1300 shown in Figures 1-8, 12, 13, 15, and 16, for example.

[0164] FIG. 23 illustrates an exemplary sensor band 1900 including a band 1952 and an electronic module 1956, according to at least one embodiment of the present disclosure. The band 1952 is configured for infants with an adjustable size to fit radial, humeral, tibial, dorsal, and / or femoral pulse points, according to at least one embodiment of the present disclosure. The electronic module 1956 may not be fully sealed and may be wrapped in a disposable film or encased in a clamshell housing. The clamshell housing may be molded from a soft elastomeric material such as silicone, polyurethane, styrene copolymer, olefin copolymer, polyolefin, or EVA, or a more rigid material such as PETG, PET, nylon, polycarbonate, or ABS. The clamshell housing may be temporarily closed with a friction fit and / or bosses, or permanently closed with adhesive or heat staking. The clamshell housing may also be permanently attached to the band 1952 with adhesive or heat welding, or temporarily attached with a hook-and-loop fastening material. The proximity sensor located on the band 1952 opposite the electronic module (not shown) may be configured as any one or more of the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, 1300 described in Figures 1-8, 12, 13, 15, and 16.

[0165] The electronic module 1956 includes an electronic circuit 1954 and a battery 1972. Electrode leads 1958 are connected to the proximity sensor on the opposite side of the band 1952 and may be fed into the clamshell housing of the electronic module 1956 through slots defined in the sidewalls, in the gap between the lid and bottom of the clamshell housing, or through the bottom of the clamshell housing, with alignment facilitated by molded features in the clamshell housing. Bosses may be used to secure the electronic circuit 1954 within the clamshell housing and provide sufficient spring force to maintain electrical contact between the electrode leads 1958 and the electronic circuit 1954. Magnets may be used to aid alignment and secure the connection between the electrodes and the electronic circuit in the clamshell housing.

[0166] Conductive material may be incorporated into the band 1952, tray / clamshell housing, and / or proximity sensor structure, which is electrically connected to a ground plane or an antenna on the electronic circuitry 1954 to improve wireless performance. A schematic cross-sectional view of a sensor band 1900 with a band 1952 configured for use with an infant is described below in connection with FIG.

[0167] FIG. 24 shows a schematic cross-sectional view of a sensor band 1900 including an infant band 1952 and an electronic module 1956 as shown in FIG. 23 , according to at least one embodiment of the present disclosure. As described in connection with FIG. 23 , the band 1952 is configured in an infant size. Now, referring to both FIGS. 23 and 24 , the sensor band 1900 includes a disposable proximity sensor 1975 secured to the band 1952 and covered by a sealing layer 1936. The sealing layer 1936 includes an adhesive 1937 for attaching to the band 1952 and the first dielectric layer 1902. The band 1952 may be formed of a low-profile loop fabric 1978 disposed over a neonate form 1980.

[0168] The disposable proximity sensor 1975 includes a first dielectric layer 1902 having an electrically conductive layer 1906 connected to a sensing electrode 1904. The sensing electrode 1904 is secured to the band 1952 by a strong hook material 1974 having an adhesive and is electrically connected to a conductive bump 1976 disposed on a shell 1960 configured to receive an electronic module 1956. The sensing electrode 1904 is electrically connected to the conductive bump 1976 by a connector, shown in FIG. 23 as a flexible flat cable 1926 (FFC), which extends from the disposable proximity sensor 1975 to the shell 1960 for electrically connecting to the electronic module 1956. The second dielectric layer 1906 is disposed between the sensing electrode 1904 and the first dielectric layer 1902. A third dielectric layer 1908 having an adhesive is attached to the FFC 1926 on one side and to the neonatology form 1980 of the band 1952 on the other side by another adhesive layer 1912. Thus, the sensing electrode 1904 is electrically connected to the electronic module 1956 .

[0169] In one embodiment, sealing layer 1936 can be a 25 μm polyurethane layer with adhesive layer 1937 known in the industry as Tegaderm. In one embodiment, first dielectric layer 1902 can be a 12 μm PET layer with an aluminum (AL) electrically conductive layer 1906. In one embodiment, second dielectric layer 1906 can be 2.5 μm PET. In one embodiment, third dielectric layer 1908 can be 25 μm polypropylene with an acrylic adhesive. Adhesive layer 1912 is a 12 μm ultra-thin acrylic transfer tape. In one embodiment, band 1952 is ~(6-8) inches in length, which is sized for an infant wearer. Notwithstanding the example dimensions provided in this section, the dimensions of the various dielectric layers of the proximity sensor 1975 may be selected according to the dimensions described herein in connection with proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, 1300 shown in Figures 1-8, 12, 13, 15, and 16, for example.

[0170] 25 illustrates a system 2000 employing the sensor band and proximity sensor described herein in connection with FIGS. 1-24, in accordance with at least one aspect of the present disclosure. Generally, system 2000 includes circuitry that processes signals received by the proximity sensor circuitry and converts the signals to analog signals that can be read directly by a bedside monitor, emulating the conversion of an arterial line.

[0171] The system 2000 includes a sensor band 2002 in communication with a data receiver 2004 and, optionally, a data monitor interface 2006. The sensor band 2000 is representative of the sensor bands 1800, 1900 described in connection with FIGS. 21-24. The sensor band 2002 includes a sensor circuit module 2008 (e.g., a printed circuit board assembly (PCBA) and firmware) for detecting signals from a patient's body using any one of the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 described in FIGS. 1-8, 12, 13, 15, and 16. In one aspect, the signal detected by the proximity sensor is a pulse waveform representative of one or more physiological parameters, including, for example, blood pressure. In one aspect, the sensor band circuit module 2008 includes a sensor circuit 4324 and a conversion circuit 4326, as described herein below in FIG. 28. The sensor band circuit module 2008 provides pairing, authentication, and sensor data to the receiver circuit module 2012 portion of the data receiver 2004 via a wireless communication standard, such as Bluetooth Low Energy (BLE) (2026). The receiver circuit module 2012 provides pairing authentication to the sensor circuit module 2008 (2028). The sensor circuit module 2008 also provides power and communication status (2024) and calculates the signal-to-noise ratio (2010).

[0172] The data receiver 2004 comprises a circuit module 2012 including hardware and software for processing signals received from the sensor band 2002 circuit module 2008. In one aspect, the receiver circuit module 2012 comprises an electrical signal detection circuit 4327 and a communication circuit 4330, as described herein below in FIG. 28 . The circuit module 2012 also provides pairing authentication 2028 to the sensor band 2002 circuit module 2008. The receiver circuit module 2012 executes 2016 a neural network algorithm to grade signal quality and provides signal filtering. The receiver circuit module 2012 also executes machine learning algorithms 2018 to extract physiological parameters such as blood pressure (BP) and other physiological parameters from sensor data received from the sensor band 2002 circuit module 2008. The receiver circuit module 2012 is connected to a user interface 2014 to provide 2030 power status, communication status, real-time waveforms, and physiological parameters such as BP. The user interface 2014 receives 2032 the demographic data, pairing commands, and data quality indicators for use within the neural network and machine learning algorithms by the receiver circuit module 2012.

[0173] The optional data monitor interface 2006 comprises a data monitor circuit module 2020 configured to receive information from the receiver circuit module 2012. The data monitor circuit module 2020 converts 2022 the digital data input received from the receiver circuit module 2012 into an analog data output 2034 suitable for a bedside monitor.

[0174] Data can be transferred wirelessly from the proximity sensor and sensor band 2002 to a data receiver 2004, which can be implemented as a mobile device, through a standard protocol, e.g., Bluetooth. Data can be cached and transmitted in bursts or variable packet sizes, e.g., DLE, to improve transmission efficiency. Data can also be stored locally in the sensor band electronics module 2008 or on the data receiver 2004 (e.g., a mobile device) for later post-processing.

[0175] The data may be preprocessed using Fourier analysis and / or bandpass filtering by the sensor band electronics module 2008 or on the data receiver 2004 (e.g., a mobile device). The SNR may be used to grade the quality of the data and select the sensor data stream to transmit only the best channels to the receiving device. The accelerometer or reference sensor data at the sensor band 2002 may be used to identify and / or quantify specific activities and may also be used to identify noise data (e.g., motion artifacts) that should be flagged or filtered out for further analysis.

[0176] The data can be processed locally on the sensor band electronics module 2008, on the data receiver 2004 (e.g., mobile device / base station), or in the cloud to extract relevant information, e.g., signal quality, hemodynamic parameters such as blood pressure, pulse height, heart rate, BP, and heart rate (HR) variability, trends, and event probabilities.

[0177] The method for ensuring in-band pairing of Bluetooth radios involves using the data channel of an inductive charging system to pass a key from the transmitting module 2008 to the receiving module 2012, allowing the transmitting and receiving devices 2002, 2004 to be securely paired. This eliminates the safety concerns of in-band pairing, removes the complexity of manual pairing, and automates the pairing process, requiring no additional hardware, only software routines to manage the pairing process. This technique may be applied to other inductive charging methods, such as radio frequency power delivery, or contact-based charging means, such as contact pins.

[0178] Methods for inductive charging energy shielding include the inductive charging system relying on a connected electromagnetic transmit-receive system that can expose the electronics on the data receiver 2002 to electromagnetic energy. This energy can result in eddy currents in the receive printed circuit board assembly (PCBA) electronics module 2012, which can then generate heat in the PCBA. One way to address this issue is to shield the receive PCBA from the electromagnetic energy by attaching a thin ferrite sheet between the receive coil and the PCBA behind it.

[0179] Additional proximity sensor circuits and related detection methods are disclosed in International Application Publication No. WO2017 / 172978A1, which is incorporated herein by reference in its entirety, and portions of referenced International Application Publication No. WO2017 / 172978A1 are reproduced herein below for convenience.

[0180] Various aspects are directed to proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, 1300 and related detection methods described in Figures 1-8, 12, 13, 15, and 16 for detecting changes in hemodynamics (or pulse waveform) of a user.

[0181] In certain exemplary embodiments, embodiments of the present disclosure include one or more sensor circuits configured and arranged to detect hemodynamic changes (or pulse waveforms) in a user, with the sensor circuit configured in a manner that monitors physiological changes in the user by using a single electrode placed near / on the surface being measured. This and other embodiments employ sensor circuits configured to detect hemodynamic changes in accordance with another of the following embodiments and / or mechanisms.

[0182] A more specific exemplary embodiment is directed to a device having at least one sensor circuit, the sensor circuit including an electrode, and an electrical signal detection circuit. The device can be used to monitor one or more hemodynamic parameters in real time in a noninvasive manner. For example, while the sensor circuit is positioned near or on the skin, the electrical signal detection circuit can detect pulse wave events by monitoring changes in capacitance. The change in capacitance transmitted by the electrode responds to pressure and / or electric field modulation, which may be due to a pulse wave event or changes in pressure or blood flow within a blood vessel (e.g., hemodynamics). The electrode can be used to determine changes in capacitance between the electrode and the user's skin. The sensor circuit including the electrode can be configured with a conversion circuit used to provide an electrical signal indicative of the change in capacitance and / or pressure to the electrical signal detection circuit. A pulse wave event may change the distance between the user's skin and the electrode and / or change the electric field distribution around a blood vessel, resulting in a relative change in the capacitance measured using the sensor circuit. The change in capacitance over time can be processed by an electrical signal sensing circuit and used to generate and / or determine a pulse waveform. In various embodiments, the pulse waveform is correlated to various hemodynamic parameters. As specific examples, the pulse waveform can be processed to determine heart rate, blood pressure, arterial stiffness, and / or blood volume.

[0183] The electrode portions of proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 shown in Figures 1-8, 12, 13, 15, and 16 may be in contact with and / or close to the user's skin. In some embodiments, the electrodes are constrained on the user (whether in contact or not) using mechanical restraints (e.g., wristbands, elastic conforming bands, or articles of clothing) and / or adhesives. The electrodes may be placed near blood vessels, preferably near palpable pulse points such as, but not limited to, the radial, brachial, carotid, tibial, and temporal pulse points.

[0184] In other specific embodiments, the device includes multiple electrodes. For example, the device may include multiple sensor circuits, each including one of the multiple electrodes. The multiple electrodes may be arranged as part of a conversion circuit that responds to modulation of the distance, pressure, and / or electric field between the user's skin and the electrodes and is used to provide an electrical signal (e.g., digital) to an electrical signal detection circuit that is indicative of changes in capacitance that may be due to hemodynamic or pulse wave events. In various related embodiments, the multiple sensor circuits are mechanically separated and / or arranged in an array (e.g., a sensor array). Each of the sensor circuits may be constructed differently, such as to have different geometries, dielectric layers, locations, sensitivities, among other structures as further described herein.

[0185] Various aspects are directed to methods of using the above-described device. The method may include placing at least one electrode of the device near or on a user's skin and detecting a pulse wave event. The pulse wave event may be detected using the device's electrical signal detection circuitry by monitoring changes in capacitance responsive to pressure and / or electric field modulations that may be attributable to hemodynamics or a pulse wave event while the at least one electrode is positioned near or on the user's skin. The pulse wave event may be used to generate a pulse waveform and / or to determine various hemodynamic parameters. For example, the method may include using the pulse wave event to determine diastolic blood pressure, systolic blood pressure, arterial stiffness, and / or blood volume.

[0186] A specific method may include using a flexible or bendable substrate of a wearable device to secure a conversion circuit having at least one sensor circuit. The substrate supports and at least partially surrounds the conversion circuit and the electrical signal detection circuit. The substrate further conforms to a portion of the user, including a blood vessel, and positions at least one electrode sufficiently close to the user's skin to electrically detect hemodynamic or pulse wave events via capacitance changes. The capacitance changes respond to pressure and / or electric field modulations that may result from hemodynamic or pulse wave events. The conversion circuit converts the capacitance changes into an electrical signal. The method further includes detecting hemodynamic or pulse wave events in response to an electrical signal from the conversion circuit via the electrical signal detection circuit, and using communication circuitry within or external to the wearable device to respond to the electrical signal detection circuit by transmitting hemodynamic monitoring data to external circuitry.

[0187] Another aspect is directed to an apparatus for use as part of a wearable device featuring a flexible or bendable substrate that supports and at least partially surrounds a transducer circuit and an electrical signal sensing circuit and is constructed and arranged to conform to a portion of a user including a blood vessel for hemodynamic monitoring. As previously described above, the apparatus includes a transducer circuit having at least one sensor circuit including an electrode, an electrical signal sensing circuit, and a communication circuit.

[0188] Aspects of the present disclosure are believed to be applicable to a variety of different types of devices including user-worn sensor circuitry constructed and arranged to sense aspects, conditions, and / or attributes of a user's pulse wave events, as well as methods involving the use of user-worn sensor circuitry. While in particular implementations, aspects of the present disclosure are shown to be beneficial when used in the context of a wrist-placed or wrist-worn strap, it will be understood that the present disclosure is not necessarily so limited. Various aspects can be understood through the following description of non-limiting examples using illustrative contexts.

[0189] Various aspects of the present disclosure are directed to a device including at least one sensor circuit having electrodes and an electrical signal detection circuit. The device can be used to monitor one or more hemodynamic parameters and pulse wave events in real time in a non-invasive manner. Surprisingly, it has been discovered that a common floating ground and a single electrode, which do not need to contact the user's skin, can be used to measure pulse wave events. In various aspects, pulse wave events can be monitored in a hands-free manner without interference from environmental noise (e.g., human voice and other background noise, electrical interference, and ambient light). The electrode (or array of electrodes) can consume a relatively small amount of power (e.g., 5 microwatts to 3 milliwatts, although aspects are not so limited). In some specific aspects, power consumption can be further reduced by simply conserving data after a trigger event (e.g., the occurrence of a specific cardiac event, such as a heart rate above a threshold or an event indicating a problem) and / or transmitting the conserved data in burst transmissions. The electrical signal sensing circuit may sense a pulse wave event by monitoring a pressure differential or a change in capacitance that may be due to a pulse wave event while at least one electrode is positioned near or on the skin.

[0190] The electrodes can be used to determine changes in capacitance between the electrodes and the user's skin. A pulse wave event can change the distance between the user's skin and the electrodes, resulting in a relative change in capacitance and / or signal amplitude and quality measured by the conversion circuit and electrical signal detection circuit. The change in capacitance over time can be processed by the electrical signal detection circuit and used to generate and / or determine a pulse waveform. In various embodiments, the pulse waveform can be correlated to various hemodynamic parameters. As a specific example, the pulse waveform can be processed to determine heart rate, blood pressure, arterial stiffness, and / or blood volume.

[0191] The electrodes may be in contact with and / or close to the user's skin. In some examples, the electrodes may be close enough to the user's skin to electrically sense hemodynamic or pulse wave events via changes in capacitance transmitted by the electrode (or electrodes). In such examples, "close enough" corresponds to a range of distances from 1 millimeter (mm) away from the skin to a closest distance of zero, or a close distance relative to the portion of the skin that contains the blood vessel. In some embodiments, the sensor circuit (e.g., electrodes) is constrained on the user (whether in contact or not) using mechanical constraints (e.g., flexible or bendable substrates such as wristbands, socks, gloves, sleeves, or other wearable devices or clothing) and / or adhesives.

[0192] The capacitance changes transmitted by the electrodes and respective sensor circuits respond to pressure and / or electric field modulations that may result from hemodynamic or pulse wave events. More specifically, the sensor circuits and electrodes may capture (or detect) capacitance changes through proximity sensing of the user's skin (as opposed to physical deformation of the device as in traditional capacitance sensors), thereby functioning as or being a proximity sensor. The proximity sensing and / or capacitance changes respond to modulations of the distance and / or fringe field lines between the user's skin and the sensor circuit.

[0193] In other specific embodiments, the device includes multiple electrodes. The multiple electrodes may be arranged as part of a conversion circuit used to provide a signal indicative of changes in capacitance and / or pressure to the electrical signal detection circuit. For example, the conversion circuit may have multiple sensor circuits, each of which includes one of the multiple electrodes. The electrical signal detection circuit may be arranged with the conversion circuit to monitor pressure differences of less than 1 kPa, such as in the range of 0.3 kilopascals (kPa) to 1 kPa. The different electrodes may have different geometries, sensitivities, and / or be in different locations. The conversion circuit may convert changes in capacitance into an electrical signal (e.g., a digital signal). As described herein, the conversion circuit and the electrical signal detection circuit may be supported by and at least partially surrounded by a substrate.

[0194] Certain aspects of the present disclosure are directed to methods of using the device, as described above. The method may include placing at least one electrode of the device near or on a user's skin and detecting a pulse wave event. The pulse wave event may be detected using the device's electrical signal detection circuitry by monitoring a pressure differential and / or a change in capacitance (or a relative capacitance change) that may be due to the pulse wave event while the at least one electrode is positioned near or on the user's skin. The pulse wave event may be used to generate a pulse waveform and / or to determine various physiological and / or hemodynamic parameters. For example, the method may include using the pulse wave event to determine diastolic blood pressure, systolic blood pressure, arterial stiffness, and / or blood volume.

[0195] Somewhat surprisingly, pulse wave events can be monitored using one or more electrodes placed on or near an arterial pulse point. For example, in response to a pulse wave event, each electrode can provide a signal indicative of the pulse wave event. The electrode (or electrodes) is connected to a circuit, such as a conversion circuit. More specifically, each electrode (e.g., an electrical conductor) is connected to a respective sensor circuit used to measure or detect a signal indicative of the pulse wave event (e.g., a capacitance value and / or change in capacitance) from the electrode and provide the signal to the conversion circuit. The conversion circuit then converts the signal indicative of the pulse wave event into an electrical signal provided to the electrical signal detection circuit. The pulse wave event is caused by a heartbeat (e.g., a contraction of a heart muscle) (e.g., a heartbeat or sound, a blood pulsation, etc.) and / or includes or signifies a hemodynamic response and / or attribute indicative of the heartbeat. The electrical signal detection circuit (and / or conversion circuit) can include commercially available or custom-designed circuitry for a capacitive touchscreen and can communicate wirelessly or via wires with a central processing unit (CPU). Additionally, the transducer circuitry and / or sensor circuitry may have a floating ground. The signal measured using the electrodes may be due to small pressure differences and / or surface displacements of the skin that modulate the fringe field at the electrodes, resulting in a measurable change in capacitance. The electrodes may be attached to the skin of a user (or other animal or creature) using an adhesive (e.g., tape) or mechanically using a strap such as a watch band, bracelet, or wristband.

[0196] In specific embodiments, the electrodes are encapsulated with a dielectric layer (e.g., an encapsulant). When multiple electrodes are used, the dielectric layer on each of the multiple electrodes may have different structural characteristics to modulate the signal sensitivity of each electrode. Exemplary characteristics may include the thickness of the dielectric layer, the composition, structure, and resistivity value of the dielectric material used, among other characteristics. Each of the multiple electrodes may be associated with different characteristics based on at least one of the electrode geometry and the dielectric layer used in the electrode. Different electrodes may be used to output signals in response to monitored pulse wave events. Signals from different electrodes may be used in differential mode to remove signals that may be common to the electrodes, such as temperature changes and user movement (e.g., noise), and to enhance signals or pulse wave events that may be measured by higher sensitivity electrodes, such as pulse wave pressure differential. In related specific embodiments, one or more electrodes of the multiple electrodes may be electrically shielded or isolated from each other. Additionally, a spacer may be used to control or set the distance between the sensor circuit and / or at least one of the electrodes and the user's skin.

[0197] The signals provided by the electrodes can be used to determine various hemodynamic parameters. For example, in response to a pulse wave event, one or more signals indicating a change in capacitance are provided to an electrical signal sensing circuit. As previously described, the change in capacitance transmitted by at least one electrode responds to pressure and / or electrical field modulation that may result from a hemodynamic or pulse wave event. The electrical signal sensing circuit uses the one or more signals to determine heart rate, diastolic blood pressure, systolic blood pressure, arterial stiffness, and other hemodynamic parameters. The signals can be processed using one or more bandpass filters or other signal processing techniques. For example, the signals can be filtered digitally or through circuit design used to minimize artifacts due to factors such as pressure changes or respiratory movement, arm movement, and external vibrations. Alternatively, characteristics of the artifacts can be isolated and quantified to extract parameters such as the user's respiration rate and movement. In one embodiment, respiration rate can be measured from body movement, and in another embodiment, it can be measured from the pulse waveform.

[0198] This surprising discovery may be particularly useful for noninvasive and / or continuous monitoring of blood pressure or other hemodynamic parameters. In a specific implementation, the device may be used to provide sensitivity to pressure differentials and / or capacitance changes caused by pulse wave events. Furthermore, the device and / or portions of the device (e.g., electrodes) may be easier to manufacture than capacitive sensors, having fewer design elements and materials, making the final device more robust.

[0199] In a related specific implementation, the apparatus includes or is part of a portable / wearable device and / or apparatus that can continuously monitor heart rate and other hemodynamic effects such as diastolic blood pressure, systolic blood pressure, and arterial stiffness. As an example, a smart bandage can be applied over an arterial pulse point and transmit data in real time to a receiver. Another example includes a smart watch band that provides real-time readings and stores and / or transmits data. Other implementations target small surface displacements or pressure differentials that can modulate fringe fields at electrodes.

[0200] Turning now to the figures, FIGS. 26A-26B show examples of devices according to the present disclosure. As shown in FIGS. 26A-26B, each device includes a sensor circuit having electrodes and an electrical signal detection circuit. The device may monitor changes in pressure differential and / or capacitance that may be attributable to pulse wave events and may use the monitored changes in pressure differential and / or capacitance to determine one or more hemodynamic parameters. The pulse wave events may be used to generate a waveform or portion of a waveform that is responsive to or indicative of a user's or an animal's pulse (e.g., representing the tactile palpation of a heartbeat). The pulse wave events may be captured as signals and used to determine hemodynamic parameters such as heart rate, diastolic blood pressure, systolic blood pressure, and / or arterial stiffness.

[0201] FIG. 26A shows an exemplary device comprising a sensor circuit 4103 including an electrode 4102 and an electrical signal sensing circuit 4106. The electrode 4102 may be placed near or on the skin of a user (or another animal). The electrical signal sensing circuit 4106 may include a proximity electrical signal sensing circuit that detects pulse wave events while the electrode 4102 is placed near or on the skin of the user. In some embodiments, as further illustrated herein, the electrode 4102 may be in direct contact with the skin or may be electrically or mechanically isolated from the skin, such as by air or a dielectric material. The electrode 4102 is used to sense changes in pressure and / or capacitance that may be attributable to pulse wave events and output a signal indicative of the detected pressure or capacitance change to the electrical signal sensing circuit 4106 via the sensor circuit 4103 and communication path 4104 (e.g., the electrode is connected or plugged into the sensor circuit 4103, which captures and outputs a signal indicative of the capacitance value). The electrical signal sensing circuit 4106 monitors changes in pressure or capacitance (or relative capacitance changes) that may be attributable to pulse wave events and determines hemodynamic parameters such as heart rate from the changes. The changes in pressure and / or capacitance may be measured based on relative changes in capacitance that may be caused by changes in the distance between the electrodes 4102 and the user's skin and / or changes in the electric field around blood vessels.

[0202] In specific embodiments, the sensor circuit 4103 and / or electrode 4102 (or electrodes) are mechanically constrained to the skin or other body part, such as by a wristband or piece of clothing. The mechanical constraining can be via an elastic, flexible, or bendable band and / or adhesive that attaches the sensor circuit 4103 and / or electrode 4102 to the skin or body. The adhesive can be applied to the periphery of the sensor circuit 4103 (not necessarily between the electrode 4102 and the skin or other body part). In other embodiments, the electrode 4102 is not physically touching the skin, such as via a spacer or in other ways, as further described herein. The change in capacitance of the subject may be relative and not an absolute value. The base capacitance of the electrode 4102 may depend on the respective geometry and extent of the electrode 4102 and / or sensor circuit 4103 design. In an exemplary experimental embodiment, the electrical signal sensing circuit 4106 may measure an input range (e.g., change in capacitance) of ±15 picofarads (pF) with a maximum offset of 100 pF. The base capacitance may be on the order of 5 to 75 pF, and the resulting pulse waveform signal (from a pulse event) may have a maximum amplitude on the order of 0.1 to 1 pF. However, embodiments are not so limited, and such values ​​may be varied for different applications through sensor and electronic design.

[0203] The relative change in capacitance over a period of time can be used to generate and / or otherwise output a pulse waveform signal. The pulse waveform signal can indicate hemodynamic parameters and / or include an arterial pulse wave (sometimes referred to as an "arterial pressure wave"). Changes in capacitance that can result from a pulse wave event can be used to determine hemodynamic parameters such as heart rate, diastolic blood pressure, systolic blood pressure, mean arterial pressure, and / or arterial stiffness. As can be understood by those skilled in the art, the arterial pulse waveform is the waveform generated by the heart as it contracts and the wave travels along the arterial walls of the arterial tree. Generally, there are two main components of this wave: a forward-traveling wave and a reflected wave. The forward wave is generated when the heart (ventricles) contracts during systole. This wave travels from the heart down the large aorta and is reflected at the aortic bifurcation or "junction" into the two iliac vessels. In a normal, healthy person, the reflected wave may return during the diastolic phase after the aortic valve closes. The returning wave has a notch, which also pushes blood through the coronary arteries, thus aiding in the perfusion of the heart through the coronary vessels. The speed at which the reflected wave returns becomes very important; the stiffer the artery, the faster it returns. This then enters the systolic phase, which can enhance the final blood pressure reading. The arterial pulse wave travels faster than the expelling blood.

[0204] The exemplary device shown in FIG. 26A (shown in FIG. 26B) may be modified in various ways as shown in FIG. 26B. One exemplary modification includes modifying the electrode 4102 so that it is electrically insulated from the user's skin. The electrode 4102 may be insulated by adding a dielectric layer to a portion of the electrode 4102 and / or by surrounding (e.g., encapsulating) the electrode 4102. In some specific embodiments, the electrode 4102 may be connected to circuitry included in the wristband (e.g., a sensor circuit such as a circuit board or chip). The electrode 4102 may be flexible. For example, the electrode 4102 may be bent around the wristband and hidden inside the wristband while worn by the user. In other examples, and / or in addition, the electrode 4102 may be incorporated and / or embedded within the wristband. The dielectric layer may be formed of a variety of different dielectric (or insulating) materials, such as polyester (e.g., polyethylene terephthalate), polyolefin, fluorinated polymer, polyimide, polyvinyl chloride, cellulose, paper, cloth, and / or other insulating materials. Additionally, the dielectric layer may have different thicknesses, such as on the order of 5 to 250 microns. Although the embodiment is not so limited, the dielectric layer may be thicker or thinner to affect the stiffness and / or comfort of a user wearing the device or to modulate the sensitivity of the sensor circuit 4103.

[0205] The shape of the pulse waveform may vary for different users and / or may be based on the location of measurement. For example, a wider pulse pressure may suggest or indicate aortic regurgitation (such as when arterial pressure drops during diastole, filling the left ventricle through the regurgitating aortic valve). A narrow pulse pressure may indicate cardiac tamponade or any other type of low-output condition (e.g., severe cardiogenic shock, massive pulmonary obstruction, or tension pneumothorax). Furthermore, the shape of the pulse waveform may adjust depending on the location of measurement, such as the further away from the aorta (e.g., brachial artery, radial artery, femoral artery, and dorsalis pedis). However, with a change in waveform shape, the mean arterial pressure (MAP) may not change and / or change within a threshold amount. This is because there is little change in resistance to flow from the aorta to the radial artery. MAP begins to change as you move into the arterioles. The change in shape from the aortic location to the dorsalis pedis can include an increase in the systolic peak, a dicrotic notch further away from the systolic peak, a lower end-diastolic pressure (e.g., a wider pulse pressure), and a later arrival of the pulse (e.g., a 60 ms delay in the radial artery from the aorta). The resulting shape is sometimes referred to as distal systolic pulse amplification because the systolic peak is steeper and further down the arterial tree.

[0206] Embodiments according to the present disclosure use devices, including wearable devices including noninvasive sensor circuits, to output pulse waveforms and determine various hemodynamic parameters. The devices can be used to monitor heart rate, diastolic blood pressure, systolic blood pressure, arterial stiffness, blood volume, and other parameters. Previously invasive devices, such as arterial lines, are medically inserted into the user, which can be painful, restrict the patient's movement, and put the user at risk for infection and other complications. For example, an arterial line is a thin catheter inserted into a user's artery. Often, the catheter is inserted into the radial artery in the wrist, but it can also be inserted into the brachial artery at the elbow, the femoral artery in the groin, the dorsalis pedis artery in the foot, and / or the ulnar artery at the wrist. Arterial lines can be used in intensive care medicine and anesthesia to directly monitor blood pressure in real time. Because insertion can be painful, an anesthetic (e.g., lidocaine) can be used to make the insertion more tolerable and to help prevent vasospasm. Complications from arterial lines can lead to tissue damage and even amputation. A device according to the present disclosure can be used to monitor blood pressure in real time in a non-invasive manner. The device can avoid and / or reduce the risks posed by invasive devices, such as temporary arterial occlusion, pseudoaneurysm, hematoma formation or bleeding at the puncture site, abscess, folliculitis, median nerve palsy, suppurative thromboarteritis, air embolism, compartment and carpal tunnel syndromes, and nerve injury.

[0207] As shown in FIG. 26B, various characteristics can be modified to adjust the sensitivity of the device and / or improve the signals obtained by the electrodes. FIG. 26B shows an exemplary device including multiple electrodes 4102-1, 4102-2, and 4102-3. Each electrode 4102-1, 4102-2, and 4102-3 is used to detect changes in pressure or capacitance that may result from a pulse wave event (e.g., caused by a change in distance between the electrode and the skin surface), as described above. The electrodes 4102-1, 4102-2, and 4102-3 can be part of or form a conversion circuit 4110 that provides one or more signals to the electrical signal detection circuit 4106. The electrodes 4102-1, 4102-2, and 4102-3 can be positioned at different locations on the device to improve positional accuracy and / or to provide one or more reference signals for differential analysis. In some embodiments, each of the electrodes 4102-1, 4102-2, 4102-3 provides a signal indicative of a change in pressure or capacitance (which may be due to a pulse wave event) to the electrical signal sensing circuit 4106. In specific embodiments, the conversion circuit 4110 may have a floating ground. In other specific embodiments, at least one of the sensor circuits has a floating ground (e.g., two sensor circuits each have a floating ground, all sensor circuits each have a floating ground, etc.). Furthermore, both the conversion circuit 4110 and at least one of the sensor circuits may have a floating ground.

[0208] Although FIG. 26B (and other examples, including but not limited to FIGS. 27A, 27B, and 27D) does not show sensor circuitry connected to the electrodes and / or to each of the multiple electrodes, one skilled in the art will understand that, as previously described, according to various embodiments, each electrode is connected to a sensor circuit. Thus, the illustration in FIG. 26B and other examples do not show sensor circuitry for purposes of clarity, and is not intended to be limiting.

[0209] In various aspects, the device (e.g., the electrical signal sensing circuit 4106) may further include wireless communication circuitry. The wireless communication circuitry wirelessly communicates data from the electrical signal sensing circuit 4106 to circuitry external to the device. The communication circuitry may be configured and arranged to communicate captured changes that may be attributable to hemodynamic pulse events to external processing circuitry. The communication circuitry may be internal or external to the wearable device and / or device and may respond to the electrical signal sensing circuitry by transmitting hemodynamic monitoring data to external circuitry. Additionally, the device may include a power supply circuit 4112, as further described herein.

[0210] In some embodiments, one or more of the plurality of electrodes 4102-1, 4102-2, 4102-3 may be electrically isolated from the user's skin. As described above, the electrodes 4102-1, 4102-2, 4102-3 may be isolated by adding a dielectric layer 4108-1, 4108-2, 4108-3 to some or all of the plurality of electrodes 4102-1, 4102-2, 4102-3. The dielectric layer 4108-1, 4108-2, 4108-3 may surround each of the electrodes 4102-1, 4102-2, 4102-3 and / or the respective sensor circuitry. However, embodiments according to the present disclosure are not so limited and may include a dielectric layer that is located at a portion of the electrode and / or at an area of ​​the electrode that is positioned to contact the skin surface and / or surrounds at least a portion of the respective electrode or sensor circuitry.

[0211] As shown in FIG. 26B, the conversion circuit 4110 can be used to provide a differential mode to reduce artifacts. The artifacts can be baseline shifts due to user movement, such as limb movement, breathing, and / or changes in body temperature. In various embodiments, the different electrodes 4102-1, 4102-2, and 4102-3 of the conversion circuit 4110 have different structural and / or characteristics that are used to modify the sensitivity levels of the respective sensor circuits that include the electrodes. For example, the electrodes 4102-1, 4102-2, and 4102-3 can be different shapes (e.g., contours), can be located in different locations relative to the user and / or device, and can be formed of different materials. In other embodiments, the different structural and / or characteristics can include different compositions, structural components, textures, and / or thicknesses of encapsulant materials used to electrically isolate the electrodes. For example, the dielectric layers of each electrode 4102-1, 4102-2, 4102-3 may be formed of dielectric materials of different compositions, structures, and / or thicknesses to modify the sensitivity level and / or characteristics of the shielding used to separate the electrodes, whereby multiple electrodes may have an encapsulant constructed and arranged to set the sensitivity level of each of the multiple electrodes.

[0212] In various embodiments, the device further includes a power supply circuit 4112. The power supply circuit 4112 provides power to at least the electrical signal detection circuit 4106. In some specific implementations, the power supply circuit 4112 is a passive or inductively powered circuit, such as an inductor circuit. Exemplary power supply circuits may include batteries, solar power converters, electromechanical systems, wall plug-ins (e.g., mains power), among other power sources. Energy harvesting mechanisms that capture mechanical vibrations, thermal gradients, ambient or transmitted radiation (e.g., RFID, Bluetooth, WiFi, UHF, and other beacon technologies) for battery-free operation are possible. In some implementations, the power supply circuit may include an inductive charging subcircuit for charging a rechargeable battery. Care may be required to isolate the inductive charging subcircuit to prevent heating due to connection to another portion of the electronic circuit.

[0213] FIG. 27A shows an example of a device including a sensor circuit having an electrode 4214 that interacts with the skin 4218. As previously described, the sensor circuit and electrode can transmit a change in capacitance through proximity sensing of the user's skin (as opposed to physical deformation as a capacitance sensor), thereby functioning as or being a proximity sensor. It has been discovered that a (proximity) sensor circuit having a single electrode 4214 placed near an arterial pulse point (e.g., artery 4216) can be used to measure the arterial pulse waveform via changes in capacitance. Heart rate and other hemodynamic parameters can be extracted from this waveform. The electrode 4214 can be in direct contact with the skin 4218 or can be electrically isolated or separated from the skin 4218. It need not be mechanically connected to the skin 4218. The composition, structure, and thickness of the electrical insulation can be selected to modify the sensitivity of the sensor. A spacer structure can be used to control the distance between the electrode and the skin. The circuit can have a floating ground (e.g., the sensor circuit and / or the transducer circuit can have a floating ground).

[0214] Arrays of electrodes can also be used to improve positional accuracy and / or to provide a reference signal for differential analysis. The signal can then be improved through electrode design that optimizes fringe field distribution. For example, in some embodiments, analog responses are sensed by an array of sensor circuits, each with a single electrode. Two or more of the electrodes in the array can have different sensitivity levels, and the analog responses sensed by two or more sensor circuits of the array can be used for differential sensing.

[0215] Figure 27B shows an example of a pulse waveform 4209 sensed using the device shown in Figure 27A. As shown, the period of the pulse waveform 4209 reflects the cardiac cycle and can be used to determine the user's heart rate.

[0216] 27C shows an exemplary mechanism for a device for monitoring pulse wave events. As shown in FIG. 27C, the user's skin 4218 serves as the ground plane for the mechanism. Without being bound to a particular theory, the mechanism behind one or more of the embodiments discussed in this disclosure is believed to be as follows: (i) the skin 4218 serves as the ground plane, and arterial pressure fluctuations result in a displacement of the surface of the skin 4218, which changes the distance between the electrode 4214 and the skin 4218, which is measured as a change in capacitance; (ii) the potential of the blood in the artery 4216 (and overlying skin) changes with each heart beat, which modifies the fringe field lines, which are reflected as a change in impedance; and (iii) a combination (contribution) of each of the above mechanisms is included.

[0217] FIG. 27D shows an example of a device as shown in FIG. 27C further including one or more spacers that set a distance (e.g., a minimum distance) between at least a portion of the sensor circuit (e.g., electrode 4214) and the skin 4218. The spacer 4217 includes one or more structures formed of a material whose length (e.g., distance from the electrode to the skin surface) sets the distance between at least a portion of the sensor circuit / electrode and the skin. The length may range from 0.1 millimeters (mm) to 1.0 mm, although embodiments are not so limited. While the embodiment of FIG. 27D shows one spacer having a rectangular shape, embodiments are not so limited and may include more than one spacer and spacers of different shapes, such as layers of textured and / or structured material.

[0218] 28 is a block diagram illustrating an exemplary method for implementing electronics and / or signal flow from a device located on or near a user's skin (e.g., including a sensor circuit 4324, a conversion circuit 4326, an electrical signal detection circuit 4327, and a communication circuit 4330) to a remote / wireless communication transceiver (e.g., received via antenna 4336) and CPU 4334 in accordance with the present disclosure. The CPU 4334 and / or electrical signal detection circuit 4327 can be programmed to perform operations as disclosed herein, including without limitation, processing the raw data to indicate the presence of specific hemodynamic signals, developing waveforms from the raw data, and / or evaluating the integrity, quality, and relevance of the hemodynamic signals and / or waveforms for specific applications related to the user's hemodynamic status or health (indicating a user's heart rate or other hemodynamic indicators or parameters, such as diastolic blood pressure, systolic blood pressure, arterial stiffness, and blood volume, and / or changes in one or more of the indicators or parameters).

[0219] The electrodes of the sensor circuit 4324 capture capacitance changes responsive to pulse wave events and provide the capacitance changes to a conversion circuit 4326. In some embodiments, the conversion circuit 4326 is or includes a capacitance-to-digital converter. The capacitance-to-digital converter converts the capacitance value (e.g., relative change) to a digital signal and outputs the digital signal to an electrical signal detection circuit 4327, which may include or be a microcontroller or other processing circuit. The electrical signal detection circuit 4327 uses power provided by a power supply 4328 to measure and / or record the arterial pulse waveform, optionally condition the signal, assess data quality, and / or determine one or more hemodynamic parameters. The electrical signal detection circuit 4327 may output the waveform and other optional data to the CPU 4334 via a communication circuit 4330 (e.g., an integrated transceiver) and antenna 4332.

[0220] As described herein, the sensing device can be used to monitor pulse wave events in a hands-free manner and without the interference of environmental noise (e.g., human voice and other background noise, electrical interference, and / or ambient light). Additionally, the electrical signal sensing circuitry can detect hemodynamic or pulse wave events in response to electrical signals from the conversion circuitry. The electrodes (or arrays of electrodes) can consume relatively small amounts of power (e.g., 5 microwatts (or less) to 3 milliwatts). In some specific embodiments, power consumption can be further reduced by simply conserving data after a trigger event and / or transmitting the conserved data in a burst transmission. The trigger event can include specific cardiac events that may indicate a problem, such as a heart rate above or below a threshold amount and / or specific waveform characteristics.

[0221] 29A-30B illustrate various exemplary devices having an array of sensors according to the present disclosure. For example, Figures 29A-30B illustrate an exemplary device having four electrodes configured to interact with a user's skin.

[0222] 29A shows a top-down (or bird's-eye) view of a device including a sensor array having four sensor circuits including four electrodes 4447, 4449, 4451, 4453. Line widths and spacing can be on the order of 0.1 mm to 20 mm for pulse monitoring applications. As shown, the sensor array includes optional ground connections 4440, 4458 and optional active shield connections 4442, 4448, 4450, 4456. The array of sensors further includes sensor connections 4444, 4446, 4452, 4454 and insulating layers 4460, 4443.

[0223] FIG. 29B shows a side view of the device shown in FIG. 29A. As shown, the layers include an insulating layer 4460, four electrodes 4445 (e.g., electrodes 4447, 4449, 4451, and 4453 shown in FIG. 29A), and another insulating layer 4443. The device includes an active portion (or region) 4455 configured for proximity to or contact with the skin of a user or other subject. The length of the active portion 4455 can be on the order of 0.1 mm to 20 mm or more for pulse monitoring applications. Furthermore, the active portion 4455 can be in contact with the skin or can be out of contact with the skin for a distance of up to 1 mm away from the skin. In various specific embodiments, the distance is typically less than 100 microns from the skin, which can be sufficient to obtain a signal with a resulting signal-to-noise value high enough to derive heart rate and / or blood pressure therefrom. In specific embodiments, the electrode 4445 may be textured or corrugated for sensitivity purposes and to reduce contact with the skin. A smaller active area may have higher sensitivity but may be more difficult to position accurately.

[0224] In various embodiments, the device includes a packaged array of sensors including (four) electrodes 4445 configured to interact with the user's skin. The array of sensors (e.g., electrodes) may be packaged in an insulating material (e.g., a dielectric material) to provide environmental stability and moisture resistance. The insulating material may include polyester, polyolefin, fluorinated polymer, polyimide, polyvinyl chloride, cellulose, paper, and cloth, among other materials. The thickness of the package may be on the order of 5 to 250 microns or more. Similarly, the optional adhesive and conductive layer thicknesses may be on the order of tens of microns, typically less than 70 and 5 microns for the adhesive and conductive layer, respectively. The conductive layer may optionally be a passive shielding layer and / or may be connected to control electronics to provide active shielding.

[0225] In a specific embodiment, the layers include an insulating layer with an optional shielding and adhesive coating, an insulating layer, one or more electrodes, another insulating layer, and another insulating layer with an optional shielding and adhesive coating, as further shown and discussed herein in connection with Figures 30A-30B.

[0226] In some embodiments, an array of sensors (e.g., electrodes) can be packaged in an insulating material (e.g., a dielectric material) to provide increased environmental stability and moisture resistance. One or more insulating layers can be cut open in one or more locations to mechanically isolate individual sensor circuits and to increase compliance of the packed sensors to the substrate underneath.

[0227] In a more specific embodiment, the packaged array of sensors includes four electrodes 4445 and a spacer layer. The spacer layer includes one or more spacers that can set or control the distance of the sensor circuit and / or electrodes (or at least a portion thereof) from the skin surface, as previously shown in FIG. 27D. The spacer layer can minimize or reduce stray capacitance from inactive (non-sensor) areas. The spacer layer thickness can be on the order of 0.1 mm to 5 mm or more, long enough that the distance does not affect sensor sensitivity. The array of sensors (e.g., electrodes) can be packaged in an insulating material (e.g., a dielectric material) to provide environmental stability and moisture resistance. The package thickness can be on the order of 5 to 250 microns or more. Similarly, the optional adhesive and conductive layer thicknesses can be on the order of tens of microns, typically less than 70 and 5 microns for the adhesive and conductive layers, respectively.

[0228] The packaged array of sensors may further include a shielding layer. As described further below, one or more insulating layers may have an adhesive coating on their inner surface to adhere one layer to another, such as by adhering one insulating layer to another. The insulating layer may have a conductive layer on its outer surface that contacts the user's skin. Alternatively, the conductive layer may be sandwiched between two insulating layers. Conductive materials may include, for example, aluminum, gold, carbon, or copper printed, evaporated, sputtered, or plated onto a non-conductive substrate (e.g., a PET or polyimide substrate). The insulating layer may be cut open in one or more locations to mechanically isolate individual sensor circuits and increase the conformability of the packaged sensor circuits to the substrate underneath. The substrate may thereby be configured and arranged as a user accessory that conforms to the user's wrist, limb, or other body part.

[0229] In a specific experimental embodiment, insulating layers 4443, 4460 and electrode 4445 are formed from flexible flat cable (FFC / FPC) cable (such as commercially available Molex 15168-0147), insulating layer 4460 with adhesive coating is formed from polyethylene terephthalate (PET) with adhesive (such as commercially available Avery 15660), insulating layer 4443 with conductive material is formed from 12 micron PET with vapor-deposited aluminum of an optical density of about or greater than 2 (such as commercially available Celplast Cel-Met 48g), and the spacer layer is formed from a layer of foam tape (such as commercially available Nexcare 731). The individual electrodes may be 0.625 mm wide with 0.625 mm spacing between them.

[0230] Different electrodes 4445 may have different capacitive sensitivities. The device may include a spacer layer that covers the active portion of some but not all of the sensor circuitry. The sensor circuitry may have separate electronics for readout to prevent or mitigate crosstalk through common circuitry.

[0231] The flexibility or flexibility of the sensor circuit as shown throughout this disclosure (including, for example, FIGS. 26A-26B, 27A, 27C-27D, 29A-29B, 30A-30B, and 31B) can be sufficient to capture pressure or capacitance changes (e.g., changes in capacitance values). More specifically, the degree of stiffness of the sensor circuit is inversely proportional to the thickness and / or length of the sensor circuit (e.g., the thicker or longer the electrodes, the stiffer they are). The flexibility and thickness (and / or length) can be configured relative to one another to be sufficient to provide sensitivity to pressure changes of 0.3 kilopascals (kPa) to 1 kPa and / or capacitance changes in the range of ±15 picofarads (pF) from the base capacitance of the sensor circuit. In more specific aspects, the flexibility and thickness and / or length can be configured relative to one another to be sufficient to provide sensitivity to pressure changes of 0.5 kPa to 1 kPa. Additionally, as described herein, measurements of pressure changes indicative of capacitance changes can be detected when the sensor circuit is in contact with the skin or other surface. Detected capacitance changes can be obtained when the electrodes are not in contact with (but within 1 mm of) the user's skin or other surface.

[0232] 30A-30B show an exemplary device having a packaged array of sensors including multiple (e.g., four) electrodes with different capacitive sensitivities. The device includes a spacer layer 4545 that covers the active portions of some sensor circuits (e.g., electrodes 4547 and 4548) but not all of the sensor circuits (e.g., not electrodes 4549 and 4550). Alternatively and / or in addition, portions of the sensor circuits (e.g., electrodes 4549 and 4550) and portions of the insulating layers 4541, 4543 are shorter in length (relative to the edge of the device proximate active portion 4551) than the remaining sensors (e.g., electrodes 4547, 4548). The sensor circuits may have separate electronics for readout to prevent or mitigate crosstalk through common circuitry. As previously mentioned, one or more of the insulating layers 4530 may have an adhesive coating on its inner surface to adhere the insulating layer 4530 to other layers, such as by adhering the insulating layer 4530 to other insulating layers 4541, 4544. The other insulating layer 4544 may have a conductive layer on its outer surface that contacts the user's skin.

[0233] 30A shows a top-down (or bird's-eye) view of a device comprising four electrodes 4547, 4548, 4549, 4550. As shown, the sensor array includes optional ground connections 4531, 4540 and optional active shield connections 4532, 4535, 4536, 4539. The array of sensors further includes sensor connections 4533, 4534, 4537, 4538, insulating layers 4541, 4543, a spacer layer 4545, and additional insulating layers 4544, 4530 with optional shielding and adhesion coatings. The insulating layers 4541, 4543 may be cut open in one or more locations 4542 to mechanically isolate individual sensor circuits and to increase compliance of the packed sensors to the substrate underneath.

[0234] Figure 30B shows a side view of the device shown in Figure 30A. As shown, the layers include an insulating layer 4530 having an adhesive coating on its inner surface (e.g., on the surface proximate insulating layer 4541), an insulating layer 4541, four electrodes 4546 (e.g., electrodes 4547, 4548, 4549, 4550 shown in Figure 30A), another insulating layer 4543, a spacer layer 4545, and another insulating layer 4544 having a conductive material on its outer surface (e.g., on the surface opposite spacer layer 4545 and / or not proximate spacer layer 4545). As previously mentioned, the device includes an active portion 4551.

[0235] FIGS. 31A-31C illustrate a device according to the present disclosure. In certain embodiments, as shown in FIGS. 31B and 31C, the device may have a flex ribbon sensor array 4602 configured and arranged to sense a pulse waveform. The flex ribbon sensor array 4602 may be held in place by a wristband 4604, as shown in FIG. 31C, which may be placed around the wrist of a user 4603. The chart shown in FIG. 31A shows capacitance data for a characteristic radial artery pulse waveform shape 4601. In an exemplary experimental embodiment, a bandpass filter (20 Hz / 0.5 Hz) is used to process the data, resulting in a calculated heart rate of 71 bpm. The reference heart rate (for a Fitbit Charge HR™) is 70 bpm, indicating that the sensor signal reflects the cardiac cycle. For this embodiment, the flex ribbon sensor array 4602 is held by an elastic wristband 4604 so that it lies flat against the user's skin. In various embodiments, a Molex 15168-0147 FFC jumper cable can be used as the flex ribbon sensor array. The heart rate can be calculated from a Fourier transform of the waveform data. The flex ribbon sensor array 4602 can be connected to a Bluetooth proximity detection circuit (e.g., an electrical signal detection circuit).

[0236] 32A-32C show exemplary data collected using a device and an arterial line according to various experimental embodiments. The data obtained using the device (placed proximate to the user's left radial pulse point) tracks and / or mimics data obtained using an arterial line implanted in the right radial artery. FIG. 32A shows that data 41773 obtained by a device according to various embodiments mimics data 41772 obtained by an arterial line. For further illustration, separately, FIG. 32B shows data 41773 (e.g., waveform) and FIG. 33C shows data 41772.

[0237] 33A-33C show exemplary pulse waveform data collected using a device and an arterial line, according to various experimental embodiments. Data obtained using a device (placed adjacent to the user's left radial pulse point) tracks and / or mimics data obtained using an arterial line implanted in the right radial artery. Heart rate can be determined in a beat-by-beat analysis by measuring pulse length. Heart rate variability can be determined from the distribution of individual heart rate values. FIG. 33A shows that pulse waveform data 41877 obtained by a device can mimic pulse waveform data 41875 obtained by an arterial line. For further illustration, FIG. 33B shows pulse waveform data 41877 (e.g., waveform) and FIG. 33C shows pulse waveform data 41875 separately.

[0238] FIGS. 34A-34C show examples of changes in heart rate and blood pressure as collected using a device and an arterial line according to various experimental embodiments. In various embodiments, patterns and abnormalities in heart rate and blood pressure may be tracked and / or monitored. The patterns and / or abnormalities may indicate various health conditions, such as atrial fibrillation, high blood pressure, peripheral vascular disease, aortic regurgitation, aortic valve stenosis, and / or left ventricular obstruction, among other conditions. Data obtained using a device (placed proximate to the user's left pulse point) may track and / or mimic data obtained using an arterial line implanted in the right radial artery. FIG. 34A shows data 41981 obtained by a device according to various embodiments mimicking data 41979 obtained by an arterial line. For further illustration, FIG. 34B shows data 41981 (e.g., waveforms) and FIG. 34C shows data 41979 separately.

[0239] As shown and described above, the pulse waveform can be used to determine various hemodynamic parameters. For example, the shape and other characteristics of the pulse waveform can be correlated to blood pressure. In other aspects, heart rate and cardiac variability can be obtained by determining the timing of each pulse. Additionally, changes in blood pressure can be monitored by first calibrating the data (such as with an arterial line calibrated against an inflatable cuff data).

[0240] A variety of different techniques can be used to analyze the pulse waveform and / or determine various hemodynamic parameters, including feature analysis and computational fluid dynamics techniques. For example, features resulting from hemodynamic phenomena can be correlated to blood pressure, arterial stiffness, and other hemodynamic parameters. For more general and specific information on the characteristics attributable to hemodynamic phenomena, see JRSM Cardiovascular Disease 1.4(2012):cvd.2012.012016, January 31, 2017, PMC, Web; Cecelia, Marina, and Phil Chowienczyk., "Role of Arterial Stiffness in Cardiovascular Disease," Journal of Applied Physiology, Vol. 16, no. 11, pp. 1396-1404, June 1, 2014; David A. Donley et al., "Aerobic exercise training reduces arterial stiffness in metabolic syndrome," Biomedical Engineering Online 13.1(2014):96; Baruch, Martin C. et al., "Validation of the pulse decomposition analysis algorithm using central arterial blood pressure." "Peripheral augmentation index defines the relationship between central and peripheral pulse pressure." and Hypertension 51.1 (2008):112-118, Munir, Shahzad et al., "Peripheral augmentation index defines the relationship between central and peripheral pulse pressure." As another example, the augmentation index (AI) (peripheral second systolic blood pressure (pSBP2) - diastolic blood pressure (DBP)) / (peripheral systolic blood pressure (pSBP) - DBP) can be used as a marker for arterial stiffness and can correlate to both peripheral and central peak blood pressure (pPP and cPP).AI is a normalized parameter and can be analyzed without absolute calibration. Computational fluid dynamics techniques can include modeling the vasculature as an inductor-capacitor-resistor (LCR) circuit and / or as an elastic tube network to calculate parameters such as pulse wave velocity and / or waveform shape. For more general and specific information related to computational fluid dynamics used to determine hemodynamic parameters, reference is made to Lee, Byoung-Kwon, "Computational fluid dynamics in cardiovascular disease," Korean Journal of Cardiology 41.8 (2011):423-430, and Xiaoman Xing and Mingshan Sun, "Optical blood pressure estimation with photoplethysmography and FFT-based neural networks," Biomedical Optics Express 7, 3007-3020 (2016), each of which is incorporated herein by reference in its entirety. One model that can be used to derive the relationship between the pulse waveform (obtained by PPG) and blood pressure includes the following: where g is defined by the coefficient E of the blood vessel wall.

number

[0241] For example, the normalized waveform may be given by:

number

[0242] Various techniques can be used to correlate the pulse waveform with blood pressure values. For more general and specific information relating to the correlation of pulse waveforms with blood pressure values, reference is made to Biomedical Optics Express 7.8 (2016): 3007-3020, Xing, Xiaoman, and Mingshan Sun, "Optical Blood Pressure Estimation with Photoplethysmography and FFT-Based Neural Networks," and http: / / cs229.stanford.edu / proj2014 / Sharath%20Ananth,Blood%20Pressure%20Detection%20from%20PPG.pdf, each of which is incorporated herein by reference in its entirety. Purpose

[0243] Uses of the sensor band 1800, 1900 device comprising a proximity sensor and firmware for detecting signals from a patient's body using any one of the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, 1300 described in this specification in Figures 1-8, 12, 13, 15, 16, and 21-24 include:

[0244] Blood pressure measurements - systolic, diastolic, mean arterial pressure, pulse pressure and their variations for both time series and trends;

[0245] vascular checks to check pulse or heartbeat as an alternative to Doppler measurements;

[0246] Monitoring blood pressure and heart rate trends for conditions such as the onset of preeclampsia, onset of hypotension in the ICU, pre-hospital hypotension for head trauma relief, post-hospital or home hypertension, intradialytic hypotension, nocturnal hypertension, masked hypertension, atrial fibrillation, premature ventricular contractions, and other heart rate irregularities, and dehydration;

[0247] Using blood pressure ratios similar to ankle-brachial index tests, or pulse height, or other metrics derived from comparison of pulse waveform shapes obtained at different locations, e.g., comparison of circulation between upper and lower body pulse points, to diagnose peripheral arterial disease, vascular complications, insufficient blood flow, or cardiac problems such as aortic stenosis; and

[0248] Transition time analysis using trends in blood pressure or pulse height, or changes in pulse waveform shape to determine complications or the effectiveness of surgical procedures.

[0249] Similar to arterial line data, other more detailed information about the cardiovascular system through pulse waveform shape relates to heart rate, heart rate variability, cardiac output, and respiratory rate.

[0250] Monitoring blood pressure and heart rate trends for hypertensive disorders such as preeclampsia affects up to 15% of pregnancies and contributes to 2.6 million preterm births, 0.5 million infant deaths, and 40% maternal deaths annually. Thus, there is an unmet need for low-cost, easy-to-use BP monitoring during the third trimester of pregnancy.

[0251] The pulse waveform shape received by the data receiver circuit module 2012 from the sensor band circuit module 2008 can be used as a biomarker for some disease states, either directly or through machine learning classification models. For example, with reference to FIGS. 35 and 36, there is some evidence that there are differences in pulse waveform shape between nominally healthy pregnant women and pregnant women hospitalized with complications. The algorithms implemented by the data receiver circuit module 2012 extract blood pressure values ​​from reasonably sufficient pulse waveform shape features for healthy pregnant women and non-pregnant women in critical care. However, data for pregnant women hospitalized in critical care is inconclusive, meaning there are differences in pulse waveform shape that could be expected, as it is assumed that some hypertensive disorders of pregnancy are due to vascular changes that occur during pregnancy.

[0252] Figure 35 is a graph of systolic blood pressure (sBP) calculated from sensor data versus arterial line sBP, according to various experimental embodiments. Figure 36 is a graph of systolic blood pressure (sBP) versus elapsed time, according to various experimental embodiments. Referring to Figures 35 and 36, a machine learning model was trained to extract systolic blood pressure (sBP) values ​​from arterial line data curated from the MIMIC-III database. The training set comprised 200 longitudinal samples randomly selected from each of 4040 critically ill patients.

[0253] In graph 3002, sBP values ​​determined from this model are shown for 174 critically ill women under the age of 45. Highlighted data points 3012, 3014, and 3016 are for three groups of women within this population who had diagnostic codes indicating pregnancy complications during their hospital stay. The remaining point 3018 is for 171 patients who did not have pregnancy-related diagnostic codes. Data point 3012 represents a woman who experienced a missed miscarriage at 22 weeks gestation. She also had hypertensive chronic kidney disease, CHF, and lupus. Data point 3014 represents a woman who gave birth to twins and experienced severe preeclampsia and its complications. Data point 3016 represents a woman who experienced a spontaneous miscarriage and benign essential hypertension, among other issues.

[0254] According to graph 3002, the model is unable to predict blood pressure values ​​for seriously ill pregnant women, but the derived blood pressures for seriously ill non-pregnant women meet FDA guidelines for accuracy.

[0255] The model was also used to derive blood pressure values ​​from sensor data 3026, 3028 for two nominally healthy pregnant women. The results are compared against upper arm cuff measurements 3030 taken simultaneously with 24-hour ambulatory blood pressure monitoring (ABPM) as a function of elapsed time in 3006. Data 3026 represents a healthy woman in the third trimester, and data 3028 represents a healthy woman in the second trimester. In both cases, it is clear that the model provides blood pressure values ​​that track the cuff values ​​as a function of time within FDA guidelines for accuracy. algorithm

[0256] Quality Model

[0257] Referring back to FIG. 25, the data receiver 2004 may be configured to process signals or data received from the sensor band 2002 comprising one or more proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, 1300 described in FIGS. 1-8, 12, 13, 15, 16 to execute algorithms 2016 to grade signal quality, provide signal filtering, calculate quality models including regression coefficient models, pulse waveform quality models, signal-to-noise ratio models, Kalman and particle filter models, artificial neural networks, and use calibration or anchor points, as described in more detail herein below.

[0258] Regression coefficient model

[0259] The pulse-by-pulse synchronized arterial and sensor data are used to determine regression coefficients that can be used as a metric of sensor data quality. When the algorithm 2016 is trained on the sensor data provided 2026 by the sensor band circuit module 2008 with the regression coefficients as ground truth values, the network can be used to predict the likelihood that subsequent sensor data will correlate to the arterial line data. This likelihood can be used as a quality metric to filter the sensor data that is fed into the algorithm 2018 used to extract blood pressure and other hemodynamic values ​​from the sensor pulse waveform data. Alternatively, it can be used to estimate the confidence level of the extracted blood pressure value.

[0260] Pulse waveform quality model

[0261] The data receiver 2004 can be configured to train another type of quality model with a quality assessment from a rubric based on pulse waveform characteristics, such as secondary peak resolution, signal-to-noise level, lack of baseline fluctuation, or motion artifacts. In one example, the pulse waveform can be visually assessed with a convolutional neural network trained on the pulse waveform data using this rubric and the assessment used as ground truth. This model can then be used to provide a quality assessment for subsequent sensor data. Like predicted regression coefficients, the quality assessment can be used to filter the sensor data for use in extracting blood pressure values ​​or estimating a confidence level for the extracted values.

[0262] Alternatively, the waveforms may be classified into different canonical shapes. A classification model may then be used to identify the class of waveform shape for each new pulse waveform. This classification may then be used to determine whether a blood pressure value can be extracted from the pulse waveform and / or which model to use.

[0263] Signal-to-Noise Ratio Model

[0264] The data receiver 2004 may be configured to implement digital filtering techniques. In one aspect, another type of quality model may be based on Fourier filtering. In this case, the data receiver 2004 may be configured to take the Fourier transform of the received sensor data. A band-stop filter may be used to remove periodic noise, such as respiratory modes at lower frequencies and oscillatory ventilation noise at higher frequencies. As is known in the art, signal power may be calculated by identifying the primary frequency of the heart rate and integrating at its peak with multiple higher harmonics (signal data). The remaining data may be integrated to determine a noise power value. The ratio of signal power to noise power yields a metric indicative of the general quality of the sensor data. When calculated over a sliding data window, the signal-to-noise ratio (SNR) may be determined as a function of time and then used to filter / select sensor data for further processing. Alternatively, signal data reconstructed from the primary frequency and its higher harmonics may be used to derive blood pressure values ​​from a BP algorithm.

[0265] Kalman and Particle Filter Models

[0266] The data receiver 2004 may be configured to implement a Kalman and particle filter, so that the received sensor data may be subjected to the Kalman and particle filters to separate the pulse waveform from other periodic signals and other artifacts, such as those due to electronic noise and motion. The separated pulse waveform data may be used in a BP algorithm to extract a blood pressure value. The fit parameters of the model may be used as a metric for signal quality. Parameters of other vibration signals, such as respiration rate, may be useful as inputs to the BP model or as information for the medical team. In one embodiment, respiration rate may be measured from body motion, and in another embodiment, it may be measured from the pulse waveform.

[0267] Any of the above quality models may also be used to determine what type of signal processing may be needed to modify the data to improve the accuracy of the predicted blood pressure value. For example, the range of frequencies used in the band-pass filter may be reduced for lower values ​​of the quality metric to filter out more motion artifacts or noise signals. In another example, the sensor data may belong to a class of data with secondary frequencies due to respiratory modes or high-frequency oscillatory ventilation, and data with these frequencies may be filtered with a band-stop filter.

[0268] Blood Pressure Model

[0269] Artificial Neural Networks

[0270] The data receiver 2004 may be configured to implement an artificial neural network (NN) to derive blood pressure values ​​from the normalized pulse waveform shape. The use of a pre-trained convolutional neural network combined with a feature-based regression model may be advantageous for this application. The incorporation of demographics such as gender, age, height, and weight may also be advantageous.

[0271] The NN code can be structured in a modular manner to allow for easy introduction of new model parameters. Due to the high correlation of sensor data with arterial line data (e.g., Figures 17-19 in WO 2017 / 172978 A1), arterial line data can be used to enhance the training set used for machine learning algorithms. The advantage of this is the breadth of available data, allowing for sampling of thousands of individuals across a wide range of demographics over long periods of time as they receive various medications and other treatments. Arterial line data taken simultaneously with sensor data can be used to derive ground truth values ​​for the sensor data pulse by pulse, providing millions of data ground truth pairs for each individual. Data from both the arterial line and the sensor may require curation to remove artifacts due to motion, scaling error, or signal compression error. Arterial line data can also be curated to remove data where the location of the arterial line makes it underdamped or overdamped, which can affect the accuracy of the reported systolic and diastolic blood pressure values. We developed an algorithm that enables automatic detection of underdamped waveforms.

[0272] Using Calibration or Anchor Points

[0273] Although uncalibrated models have been developed by the inventors using only normalized sensor pulse wave data as input, in some situations it may be advantageous to use external data to improve the accuracy of the extracted blood pressure values. For example, demographic information such as age, sex, height, and weight, as well as information regarding medical treatments such as high-frequency oscillatory ventilation, circulatory assist devices, or dialysis, may be used to select between models or as inputs to specific models. For newborns, birth weight or gestational age may also be used as inputs to the models.

[0274] The use of one or more inflatable cuff measurements at the beginning of sensor data collection may also be used as input to some models. It may also be advantageous to use periodic cuff measurements as input to models during the course of sensor data collection.

[0275] The model may also include input from a prescribed starting schedule in which the sensor is applied and then used in multiple positions. For example, one such schedule for a wrist-worn sensor may be to hold the arm up, down, and straight for a set period of time, e.g., 5-20 seconds. An altimeter may be used to convey the relative position of the sensor in the three positions and determine a calibration factor for the sensor data by applying a correction factor based on the sensor position to blood pressure values ​​extracted from the sensor data.

[0276] In various embodiments, the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 described in FIGS. 1-8 , 12 , 13 , 15 , and 16 , and / or the sensor bands 1800 and 1900 described in connection with FIGS. 21-24 , can be connected to an accessory device to reduce motion artifacts, such as vehicle or ventilator vibrations. The accessory device can include a pad of damping (e.g., viscoelastic) material to isolate the device from environmental motion, similar to the concept of vibration-isolated optical benches. The damping can be frequency-dependent and tuned to specific types of vibration. The vibration-damping material can dampen vibrations or mitigate motion artifacts. The vibration-damping pad can be placed under the arm or leg to which the sensor pad 1800 and 1900 ( FIGS. 21-24 ) is attached, or can be used as a mattress / seat pad directly under the patient. method

[0277] The following methods 5000, 6000, and 7000 shown in FIGS. 37-39 may be implemented using hardware associated with the proximity sensor circuit, electrical signal detection circuit, and signal processing circuit described in detail above. One or more proximity sensor circuits, electrical signal detection circuits, and signal processing circuits may be configured and arranged to detect hemodynamic changes (or pulse waveforms) in a user with a sensor circuit configured in a manner that monitors physiological changes in a user by using a single electrode placed near or on the surface being measured. This and other embodiments employ proximity sensor circuits, electrical signal detection circuits, and signal processing circuits configured to detect hemodynamic changes in accordance with one or more of the above hardware and methods described below. Accordingly, in the description of the methods below, reference may be made to the hardware in the description of FIGS. 1-31B and C, and the data in FIGS. 31A and 32A-35.

[0278] In particular, each of methods 5000, 6000, and 7000 may be implemented by circuit 2000 as described in FIGS. 25 and 28 connected to any one of proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 as described in FIGS. 1-8, 12, 13, 15, and 16, which may be employed to monitor one or more physiological parameters in real time in a non-invasive manner. The circuit 2000 includes a sensor band 2002 including a sensor circuit module 2008 (e.g., a printed circuit board assembly (PCBA) and firmware) for detecting signals from a patient's body using any one of the proximity sensors 100, 200, 300, 400, 500, 600, 700, 800, 1000, 1100, 1200, and 1300 (100-1300) described in FIGS. 1-8, 12, 13, 15, and 16. In one embodiment, the signal detected by the proximity sensor is a pulse waveform representative of one or more physiological parameters, including, for example, blood pressure, among others, as described herein below. In one embodiment, the circuit module 2008 includes a sensor circuit 4324 and a conversion circuit 4326, as described in FIG. 25. The sensor circuit 4324 includes at least one electrode and is connected to the conversion circuit 4326. The conversion circuit 4326 is optionally wirelessly connected to a data receiver 2004 comprising a circuit module 2012 including hardware and software to implement an electrical signal detection circuit 4327 and process signals received from the conversion circuit 4326. In one aspect, the electrical signal detection circuit 4327 of the receiver circuit module 2012 is configured to process signals received from the conversion circuit 4326. The communication circuit 4330 may communicate with the cloud for further processing of the signals and may communicate with an external monitor, such as the data monitor 2006.

[0279] 37 illustrates a method 5000 for hemodynamic monitoring according to at least one embodiment of the present disclosure. Method 5000 includes hemodynamic monitoring via a wearable device, such as a sensor band 2002, including a sensor circuit 4324 having at least one electrode 100-1300 positioned near or on a user's skin, a conversion circuit 4326 for receiving signals from the sensor circuit 4324, converting the sensed capacitance signal to a digital signal, and providing the digital signal to a signal sensing circuit 4327 for processing. Method 5000 is described herein below with reference to FIGS. 25 and 28 in conjunction with FIG. 37.

[0280] According to method 5000, the sensor circuit 4324 detects (5002) changes in a capacitance signal between the electrodes 100-1300 and the user's skin. Here, the changes in the capacitance signal represent pressure and / or electric field modulations that may be due to a pulse wave event or changes in pressure or blood flow within a blood vessel (e.g., hemodynamics). The conversion circuit 4326 converts (5004) the detected (5002) capacitance signal into a digital signal indicative of, for example, the change in the capacitance signal and / or pressure, and provides (5006) the digital signal to the signal detection circuit 4327 for digital signal processing and / or communication. A pulse wave event may change the distance between the user's skin and the electrodes and / or change the electric field distribution around the blood vessel, resulting in a relative change in capacitance measured using the sensor circuit. The signal detection circuit 4327 processes (5008) the digital signal representing the change in capacitance over time to generate and / or determine a pulse waveform. The signal detection circuitry 4327 correlates (5010) the pulse waveform data with various hemodynamic parameters and processes (5012) the pulse waveform data to determine (5014) both time series and trends, particularly heart rate, blood pressure, e.g., systolic and diastolic pressure, mean arterial pressure, pulse pressure, arterial stiffness, and / or blood volume, or combinations thereof, and their variations.

[0281] In one embodiment, method 5000 includes measuring pulse waves or heart beats as an alternative to Doppler measurements. In another embodiment, method 5000 includes measuring multiple pulse points and providing a comparison of circulation. In another embodiment, method 5000 includes determining complications or the effectiveness of a surgical procedure through circulation time analysis using trends in blood pressure or pulse height, or changes in pulse waveform shape.

[0282] Method 5000 further includes placing at least one electrode 100-1300 of sensor circuit 4324 near or on the user's skin and detecting a pulse wave event. According to method 5000, electrode 100-1300 may be in contact with and / or proximity to the user's skin. In some embodiments, electrode 100-1300 is constrained on the user (whether in contact or not) using a mechanical restraint (e.g., a wristband, an elastic conforming band, or an article of clothing) and / or an adhesive. Electrode 100-1300 may be placed near a blood vessel, preferably near a palpable pulse point, such as, but not limited to, the radial, brachial, carotid, tibial, and temporal pulse points.

[0283] According to method 5000, at least one sensor circuit 4324 comprises a plurality of electrodes 100-1300 arranged as part of a conversion circuit 4326 to provide an electrical signal (e.g., digital) to an electrical signal detection circuit 4327, the electrical signal being responsive to modulation of distance, pressure, and / or electric field between the user's skin and the electrodes 100-1300 and indicative of changes in capacitance that may be due to hemodynamic or pulse wave events. In various related aspects, the plurality of sensor circuits 4324 may be mechanically separated and / or arranged in an array (e.g., a sensor array). Each of the sensor circuits 4324 may be constructed differently, such as to have different geometries, dielectric layers, locations, sensitivities, among other structures as further described herein.

[0284] 38A-38D illustrate a method 6000 for measuring and processing one or more physiological parameters according to at least one embodiment of the present disclosure. The method 6000 includes measuring and processing one or more physiological parameters via a wearable device such as a sensor band 2002 including a sensor circuit 4324 having at least one electrode 100-1300 positioned near or on a user's skin, a conversion circuit 4326 for receiving a signal from the sensor circuit 4324, converting the signal to a digital signal, and providing the digital signal to a signal detection circuit 4327 for processing the digital signal.

[0285] Referring to FIG. 38A , in one embodiment, according to method 6000, sensor circuit 4324 detects (6002) a change in a capacitance signal between electrodes 100-1300 and a user's skin, where the change in the capacitance signal represents pressure and / or electric field modulation that may be due to a pulse wave event or a change in pressure or blood flow within a blood vessel (e.g., hemodynamics). Conversion circuit 4326 converts (6004) the detected capacitance signal into a digital signal indicative of the change in the capacitance signal and / or pressure, for example, that was detected (6002), and provides (6006) the digital signal to signal detection circuit 4327 for digital signal processing and / or communication. A pulse wave event may change the distance between the user's skin and electrodes 100-1300 and / or change the electric field distribution around the blood vessel, resulting in a relative change in the capacitance measured using sensor circuit 4324. The signal sensing circuitry 4327 processes 6008 the digital signal representing the change in capacitance over time to generate and / or determine a pulse waveform.

[0286] 38B , in one embodiment, according to method 6000, the signal detection circuit 4327 receives pulse waveform data from the conversion circuit 4326 and implements a regression coefficient model based on digital data received by the signal detection circuit 4327 corresponding to sensed physiological parameters (6010). The sensed physiological parameters include heart rate, blood pressure (e.g., systolic and diastolic pressures), mean arterial pressure, pulse pressure, arterial stiffness, and / or blood volume, or combinations thereof, and their variability, for both time series values ​​and trends. The signal detection circuit 4327 uses the pulse-synchronized arterial and sensor data to determine (6012) regression coefficients between the sensor and reference arterial line data. The signal detection circuit 4327 then employs (6014) the regression coefficients as a metric of sensor data quality.

[0287] 38B , in one aspect, according to method 6000, the signal detection circuit 4327 employs a neural network trained on sensor data using regression coefficients as ground truth values ​​(6016). The neural network is employed by the signal detection circuit 4327 to predict (6018) the likelihood that subsequent sensor data will be correlated to arterial line data when taken simultaneously. The signal detection circuit 4327 employs (6020) that likelihood as a quality metric for filtering sensor data that is fed into an algorithm to extract blood pressure values ​​from the sensor pulse waveform data. The signal detection circuit 4327 estimates (6022) a confidence level for the extracted blood pressure value based on that likelihood.

[0288] Referring to FIG. 38C, in one embodiment, according to method 6000, the signal detection circuit 4327 implements a pulse waveform quality model based on the received sensor data (6024). The signal detection circuit 4327 trains (6026) a quality assessment from a rubric based on pulse waveform characteristics, such as secondary peak resolution, signal-to-noise level, lack of baseline fluctuation, or motion artifact, or a combination thereof. The signal detection circuit 4327 visually assesses (6028) the pulse waveform data and trains (6030) a convolutional neural network on the pulse waveform data, with the assessment used as a ground truth value. In one embodiment, according to method 6000, the signal detection circuit 4327 provides (6032) a quality assessment for the subsequent sensor data for use in filtering the sensor data to extract blood pressure values ​​or estimate a confidence level for the extracted values. In one embodiment, according to method 6000, the signal detection circuit 4327 classifies (6034) the pulse waveform data into different canonical shapes to identify a waveform shape class for each new pulse waveform and determine whether a blood pressure value can be extracted from the pulse waveform and / or which model to use.

[0289] 38D , in one aspect, according to method 6000, the signal detection circuit 4327 implements a signal-to-noise ratio model based on the received sensor data (6036). The signal detection circuit 4327 implements a quality model based on a Fourier filter based on a Fourier transform of the received sensor data (6038). In one aspect, the signal detection circuit 4327 implements a bandstop filter to remove periodic noise, such as respiratory modes at lower frequencies and oscillatory ventilation noise at higher frequencies (6040). In one aspect, the signal detection circuit 4327 calculates the sensor data signal power by identifying a primary frequency associated with the heart rate and integrating at the peaks of the signal power with multiple higher harmonics of the signal data (6042). The signal detection circuit 4327 integrates at the peaks of the signal power with multiple higher harmonics of the signal data (6044). The signal detection circuit 4327 integrates 6046 the remaining data to determine a noise power value and calculates 6048 a signal power to noise power ratio to produce a metric indicative of the general quality sensor data. In one aspect, the signal detection circuit 4327 calculates 6050 a signal power to noise power ratio over a sliding data window to determine the signal-to-noise ratio (SNR) as a function of time and filter / select received sensor data for further processing. In one aspect, the signal detection circuit 4327 reconstructs 6052 the sensor signal data from the primary frequency employing higher harmonics to derive a blood pressure value.

[0290] 38D , in one aspect, according to method 6000, the detection signal circuit 4327 implements a Kalman and particle filter model based on the received sensor data (6054). The signal detection circuit 4327 processes the sensor data through the Kalman and particle filters to separate the pulse waveform from other periodic signals and other artifacts due to electronic noise and movement (6056). The signal detection circuit 4327 separates the pulse waveform data to extract a blood pressure value (6058).

[0291] 39A-39C illustrate a method 7000 for measuring and processing one or more physiological parameters according to at least one embodiment of the present disclosure. The method 7000 includes measuring and processing one or more physiological parameters via a wearable device such as a sensor band 2002 including a sensor circuit 4324 having at least one electrode 100-1300 positioned near or on a user's skin, a conversion circuit 4326 for receiving a signal from the sensor circuit 4324, converting the signal to a digital signal, and providing the digital signal to a signal detection circuit 4327 for processing the digital signal.

[0292] Referring to FIG. 39A , in one embodiment, according to method 7000, the sensor circuit 4324 detects (7002) changes in a capacitance signal between the electrodes 100-1300 and the user's skin. Here, the changes in the capacitance signal represent pressure and / or electric field modulation, which may be due to a pulse wave event or changes in pressure or blood flow within a blood vessel (e.g., hemodynamics). The conversion circuit 4326 converts the detected (7002) capacitance signal into a digital signal indicative of the change and / or pressure in the capacitance signal, which is provided (7004) to the signal detection circuit 4327, for example, for digital signal processing and / or communication. The pulse wave event may change the distance between the user's skin and the electrodes 100-1300 and / or change the electric field distribution around the blood vessel, resulting in a relative change in capacitance measured using the sensor circuit 4324. The signal detection circuit 4327 processes (7006) the digital signal representing the changes in capacitance over time to generate and / or determine a pulse waveform. The signal detection circuit 4327 implements 7008 one or more blood pressure models based on the digital data received by the signal detection circuit 4327 associated with the sensed physiological parameters.

[0293] Referring to FIG. 39B, in one aspect, according to method 7000, the signal detection circuit 4327 implements (7012) an artificial neural network and employs (7014) the artificial neural network to derive blood pressure and / or other hemodynamic values ​​from the normalized pulse waveform shape. The signal detection circuit 4327 employs (7016) a pre-trained convolutional neural network combined with a feature-based regression model. The signal detection circuit 4327 structures (7018) the neural network code in a modular manner to allow for the introduction of new model parameters. In some cases, the signal detection circuit 4327 may also be configured to measure (7020) arterial line data simultaneously with the sensor data to derive ground truth values ​​for the sensor data on a pulse-by-pulse basis. The signal detection circuit 4327 curates 7022 the pulse waveform data to remove artifacts due to motion, scaling error, or signal compression error, or a combination thereof, and curates 7024 the arterial line data to remove data in which the arterial line is under- or over-attenuated to improve the accuracy of the reported systolic and diastolic blood pressure values ​​7026. The signal detection circuit 4327 may also be configured to convert the digital data received and processed by 7012 to an analog output that can be displayed on a bedside monitor and input into the hospital's electronic medical record in the same manner as data from an arterial line transducer.

[0294] 39C , in one aspect, according to method 7000, the signal detection circuit 4327 implements calibration or anchor points (7028) and / or employs external data to improve the accuracy of extracted blood pressure values ​​(7030). The external data includes demographic information such as age, sex, height, and weight, and information regarding medical treatments such as high frequency oscillatory ventilation, circulatory assist devices, dialysis, birth weight, or gestational age, or any combination thereof. The signal detection circuit 4327 employs one or more inflatable cuff measurements at the beginning of sensor data collection as input to the model (7032), employs periodic cuff measurements as input to the model during the course of sensor data collection (7034), and / or employs input from a prescribed starting regimen to which sensor data is applied and then used at multiple locations (7036). Example

[0295] Various aspects of the subject matter described herein are set forth in the following numbered examples.

[0296] Example 1. A proximity sensor comprising: a first dielectric layer having an inner surface and an outer surface; an electrically conductive layer located proximate one of the inner surface or the outer surface of the first dielectric layer; and an electrode having an outer surface, the outer surface of the electrode located proximate the inner surface of the first dielectric layer, wherein the outer surface of the electrode and the electrically conductive layer define a gap.

[0297] Example 2. The proximity sensor of example 1, wherein the electrically conductive layer is located proximate to an outer surface of the first dielectric layer, the electrode is located proximate to an inner surface of the first dielectric layer, the electrode having an inner surface and an outer surface, the outer surface of the electrode is located proximate to the inner surface of the first dielectric layer, and the outer surface of the electrode and the electrically conductive layer define a gap.

[0298] Example 3 The proximity sensor of any one of Examples 1-2, wherein the first dielectric layer has a thickness of up to 150 μm.

[0299] Example 4 The proximity sensor of any one of Examples 1 to 3, further comprising a substrate and a second dielectric layer, the second dielectric layer having an inner surface and an outer surface, and the second dielectric layer being disposed between the inner surface of the electrode and the substrate.

[0300] Example 5 The proximity sensor of example 4, further comprising an adhesive layer positioned between the substrate and the inner surface of the second dielectric layer.

[0301] Example 6 The proximity sensor of any one of Examples 1 to 5, further comprising: an electrically conductive element electrically connected to the electrode to provide an electrical connection between the electrode and the electronic circuit; and an adhesive layer having an inner surface and an outer surface, the adhesive layer being disposed between the inner surface of the first dielectric layer and the electrically conductive element.

[0302] Example 7 The proximity sensor of example 6, wherein the electrically conductive element is disposed proximate to an inner surface of the first dielectric layer or proximate to an outer surface of the second dielectric layer.

[0303] Example 8 The proximity sensor of any one of Examples 6-7, further comprising a dielectric foam or double-sided tape disposed between the inner surface of the first dielectric layer and the outer surface of the adhesive layer.

[0304] Example 9 The proximity sensor of any one of Examples 1-8, wherein the electrically conductive layer is located proximate to an inner surface of the first dielectric layer, further comprising a second dielectric layer disposed between the electrode and the electrically conductive layer, wherein the outer surface of the electrode and the electrically conductive layer define a gap, and wherein the dielectric layer may be floating or may be fixed to other components comprising the proximity sensor to control the gap.

[0305] Example 10 The proximity sensor of example 9, wherein the second dielectric layer has a thickness of up to 150 μm.

[0306] Example 11 The proximity sensor of any one of Examples 9-10, wherein the second dielectric layer has a thickness of less than 5 μm.

[0307] Example 12 The proximity sensor of any one of Examples 9 to 11, wherein the second dielectric layer has a thickness of less than 3 μm.

[0308] Example 13 The proximity sensor of any one of Examples 9 to 12, wherein the second dielectric layer has a textured surface.

[0309] Example 14 The proximity sensor of any one of Examples 9-13, further comprising: a substrate; and a third dielectric layer disposed between the electrode and the substrate.

[0310] Example 15 The proximity sensor of example 14, further comprising a polymer layer disposed between the third dielectric layer and the substrate.

[0311] Example 16 The proximity sensor of Example 15, further comprising an adhesive layer positioned between the substrate and the polymer layer.

[0312] Example 17 A proximity sensor comprising: a first dielectric layer having an inner surface and an outer surface; an electrically conductive layer located proximate one of the inner surface or the outer surface of the first dielectric layer; a sensing electrode located proximate the inner surface of the first dielectric layer, the sensing electrode having an inner surface and an outer surface, the outer surface of the sensing electrode located proximate the inner surface of the first dielectric layer, and the outer surface of the sensing electrode and the electrically conductive layer defining a gap; and a reference electrode disposed relative to the sensing electrode, the reference electrode located proximate the inner surface of the first dielectric layer, the reference electrode having an inner surface and an outer surface, the outer surface of the reference electrode located proximate the inner surface of the first dielectric layer, and the outer surface of the reference electrode and the electrically conductive layer defining a gap.

[0313] Example 18 The proximity sensor of Example 17, wherein the adhesive layer is disposed between the inner surface of the first dielectric layer and the outer surface of the reference electrode.

[0314] Example 19 The proximity sensor of any one of Examples 17-18, wherein the reference electrode is disposed laterally relative to the sensing electrode.

[0315] Example 20 The proximity sensor of any one of Examples 17-19, wherein the reference electrode is laminated to the sensing electrode.

[0316] Example 21 The proximity sensor of any one of Examples 17-20, wherein the sensing electrode and the reference electrode are mechanically separated.

[0317] Example 22 The proximity sensor of any one of Examples 17-21, further comprising a first substrate, a second substrate, a third dielectric layer disposed between the sensing electrode and the first substrate, and a fourth dielectric layer disposed between the reference electrode and the reference electrode.

[0318] Example 23. The proximity sensor of Example 22, further comprising: a first adhesive layer positioned between the first substrate and the third dielectric layer; and a second adhesive layer positioned between the second substrate and the fourth dielectric layer.

[0319] Example 24 The proximity sensor of any one of Examples 22-23, further comprising a fifth dielectric layer disposed between the reference electrode and the first dielectric layer.

[0320] Example 25. The proximity sensor of example 24, further comprising a sixth dielectric layer disposed between the sensing electrode and the first dielectric layer.

[0321] Example 26 The proximity sensor of any one of Examples 22-25, further comprising a cover film disposed over the first and second substrates.

[0322] Example 27 The proximity sensor of any one of Examples 22 to 26, wherein the first and second substrates are arranged along the same plane.

[0323] Example 28: The proximity sensor of any one of Examples 22 to 27, wherein the first and second substrates are arranged along different planes, and the proximity sensor further comprises a mounting structure and a foam layer arranged between the first and second substrates to provide conformability and ensure that both the reference and sensing electrodes have similar contact surfaces, wherein the foam layer portion between the first substrate and the mounting structure has a first thickness, and the foam layer portion between the second substrate and the mounting structure has a second thickness different from the first thickness.

[0324] Example 29 The proximity sensor of any one of Examples 17-28, further comprising a foam layer, wherein the sensing electrode and the reference electrode are located on opposite sides of the foam layer.

[0325] Example 30 The proximity sensor of any one of Examples 17 to 29, further comprising a sealing layer disposed over the sensing surface.

[0326] Example 31 The proximity sensor of any one of Examples 29-30, further comprising a mounting structure located on the same side of the foam layer as the reference electrode.

[0327] Example 32. A proximity sensor module comprising: a sensor element substrate, wherein the sensor element comprises any one of the proximity sensors defined in any one of Examples 1 to 31; at least one electrically conductive electrode lead disposed on the sensor element substrate; at least one elastically deformable electrically conductive feature disposed on the at least one electrically conductive electrode lead; an electronics module; and at least one electrically conductive pad disposed on the electronics module, the at least one electrically conductive pad positioned to make an electrical connection between the at least one electrically conductive lead and the at least one electrically conductive pad through the at least one elastically deformable electrically conductive feature.

[0328] Example 33. The proximity sensor module of Example 32, further comprising: a plurality of electrically conductive leads; a plurality of elastically deformable electrically conductive features disposed on the plurality of electrically conductive electrode leads; and a plurality of electrically conductive pads disposed on the electronic module, the plurality of electrically conductive pads positioned to make electrical connections between the plurality of electrically conductive leads and the plurality of electrically conductive pads through the plurality of elastically deformable electrically conductive features.

[0329] Example 34 The proximity sensor module of any one of Examples 32 to 33, wherein the sensor element substrate is embossed.

[0330] Example 35. The proximity sensor module of example 34, further comprising a compliant substrate disposed below the embossed sensor element substrate to provide structural support to the embossed sensor element substrate.

[0331] Example 36 The proximity sensor module of any one of Examples 1 to 35, further comprising a clamshell housing configured to receive the electronic module.

[0332] Example 37 The proximity sensor module of example 36, further comprising a fastening member disposed between the sensor element and the clamshell housing.

[0333] Example 38: The proximity sensor module of Example 37, wherein the fastening member comprises a hook-and-loop fastening member.

[0334] Example 39: A circuit for measuring a physiological parameter, the circuit comprising: a sensor element substrate comprising any one of the proximity sensors defined in any one of Examples 1 to 31, the sensor circuit comprising at least one electrode, the sensor circuit configured to monitor a capacitance signal between the at least one electrode and a user's skin, the capacitance signal representing pressure and / or electric field modulation that may be due to a pulse wave event, movement in the user's blood vessel, a change in pressure or blood flow, or movement of a part of the user's body; a conversion circuit connected to the sensor circuit, the conversion circuit configured to convert the monitored capacitance signal into a digital signal indicative of the monitored capacitance signal; and a signal detection circuit configured to receive the digital signal and determine at least one physiological parameter associated with the user.

[0335] Example 40 The circuit of Example 39, wherein the physiological parameters include blood pressure, systolic, diastolic, mean arterial pressure, or pulse pressure, respiration rate, or combinations thereof, and variations thereof, both as time series values ​​and trends.

[0336] Example 41 The circuit of any one of Examples 39-40, wherein the signal detection circuit is configured to measure a pulse wave or heartbeat as an alternative to Doppler measurements.

[0337] Example 42. The circuit of any one of Examples 39-41, wherein the signal sensing circuit is configured to monitor trends in blood pressure and heart rate.

[0338] Example 43. The circuit of any one of Examples 39-42, wherein the electronic circuit is configured to measure multiple pulse points and provide a comparison of circulation.

[0339] Example 44. The signal sensing circuit of any one of Examples 39-43, wherein the signal sensing circuit is configured to determine complications or the effectiveness of a surgical procedure through circulation time analysis using trends in blood pressure or pulse height, or changes in pulse waveform shape.

[0340] Example 45: A circuit for measuring a physiological parameter, the circuit comprising: a sensor element substrate comprising any one of the proximity sensors defined in any one of Examples 1 to 31, the sensor circuit comprising at least one electrode, the sensor circuit configured to monitor a capacitance signal between the at least one electrode and a user's skin, the capacitance signal representing pressure and / or electric field modulation that may be due to a pulse wave event or a change in pressure or blood flow in the user's blood vessel; a conversion circuit connected to the sensor circuit, the conversion circuit configured to convert the monitored capacitance signal into a digital signal indicative of the monitored capacitance signal; and a signal detection circuit configured to implement a quality model.

[0341] Example 46. The circuit of example 45, wherein the signal detection circuit is configured to implement a regression coefficient model as a metric of sensor data quality.

[0342] Example 47: The circuit of any one of Examples 45-46, wherein the signal detection circuit is configured to employ a neural network that is trained on sensor data using regression coefficients as ground truth values, and the network is employed to predict the likelihood that subsequent sensor data will be correlated to arterial line data, and the likelihood is employed as a quality metric for filtering sensor data that is fed into an algorithm to extract blood pressure values ​​from the sensor pulse waveform data.

[0343] Example 48. The circuit of example 47, wherein the signal detection circuit is configured to employ probability to estimate a confidence level of the extracted blood pressure value.

[0344] Example 49. The circuit of any one of Examples 45-48, wherein the signal detection circuit is configured to implement a pulse waveform quality model.

[0345] Example 50 The circuit of Example 49, wherein the signal detection circuit is configured to train on quality assessment from a rubric based on pulse waveform characteristics such as resolution of secondary peaks, signal-to-noise level, lack of baseline fluctuations, or motion artifacts, or a combination thereof.

[0346] Example 51 The circuit of Example 50, wherein the signal detection circuit is configured to visually evaluate the pulse waveform and train a convolutional neural network on the pulse waveform data with the evaluation used as a ground truth value.

[0347] Example 52. The circuit of any one of Examples 49-51, wherein the signal detection circuit is configured to filter the sensor data for use in extracting a blood pressure value or providing a quality assessment for the subsequent sensor data to estimate a confidence level for the extracted value.

[0348] Example 53. The circuit of any one of Examples 49-52, wherein the signal detection circuit is configured to identify a waveform shape class for each new pulse waveform and classify the waveform into different canonical shapes to determine whether a blood pressure value can be extracted from the pulse waveform and / or which model to use.

[0349] Example 54. The circuit of any one of Examples 45-53, wherein the signal detection circuit is configured to implement a signal-to-noise ratio model.

[0350] Example 55. The circuit module of example 54, wherein the signal detection circuit is configured to implement the quality model based on Fourier filtering based on a Fourier transform of the sensor data.

[0351] Example 56: The circuit of any one of Examples 54-55, wherein the signal detection circuit is configured to implement a band-stop filter to remove periodic noise, such as respiratory modes at lower frequencies and oscillatory ventilation noise at higher frequencies.

[0352] Example 57. The circuit of any one of Examples 45 to 56, wherein the signal detection circuit is configured to calculate the signal power by identifying a primary frequency of the heart rate and integrating at the peak of the signal power along with multiple higher harmonics of the signal data.

[0353] Example 58. The circuit of example 57, wherein the signal detection circuit is configured to integrate the remaining data to determine a noise power value.

[0354] Example 59. The circuit of example 58, wherein the signal detection circuit is configured to calculate a ratio of signal power to noise power to produce a metric indicative of the general quality of the sensor data.

[0355] Example 60: The circuit of any one of Examples 58-59, wherein the signal detection circuit is configured to calculate a ratio of signal power to noise power over a sliding data window to determine a signal-to-noise ratio (SNR) as a function of time and filter / select sensor data for further processing.

[0356] Example 61. The circuit of example 60, wherein the signal sensing circuit is configured to reconstruct signal data from a primary frequency and employ higher harmonics to derive a blood pressure value.

[0357] Example 62. The circuit of any one of Examples 45-61, wherein the signal detection circuit is configured to implement a Kalman and particle filter model.

[0358] Example 63 The circuit of Example 62, wherein the signal detection circuit is configured to process sensor data that undergoes Kalman and particle filters to separate the pulse waveform from other periodic signals and other artifacts due to electronic noise and movement.

[0359] Example 64. The circuit of example 63, wherein the signal detection circuit is configured to isolate the pulse waveform data to extract a blood pressure value.

[0360] Example 65: A circuit for measuring a physiological parameter, the circuit comprising: a sensor element substrate comprising any one of the proximity sensors defined in any one of Examples 1 to 31, the sensor circuit comprising at least one electrode, the sensor circuit configured to monitor a capacitance signal between the at least one electrode and a user's skin, the capacitance signal representing movement, pressure and / or electric field modulation that may be due to a pulse wave event, a change in pressure or blood flow in a blood vessel of the user, or movement of a part of the user's body; a conversion circuit connected to the sensor circuit, the conversion circuit configured to convert the monitored capacitance signal into a digital signal indicative of the monitored capacitance signal; and a signal detection circuit configured to implement blood pressure and other hemodynamic and physiological models.

[0361] Example 66 The circuit of Example 65, wherein the signal detection circuit is configured to convert the capacitance signal into a format that can be displayed on an external monitor and / or processed and stored on an external data system.

[0362] Example 67. The circuit of any one of Examples 65-66, wherein the signal detection circuit is configured to implement an artificial neural network.

[0363] Example 68. The circuit of example 67, wherein the signal detection circuit is configured to employ an artificial neural network (NN) to derive a blood pressure value from the normalized pulse waveform shape.

[0364] Example 69. The circuit of example 68, wherein the signal detection circuit is configured to employ a pre-trained convolutional neural network combined with a feature-based regression model.

[0365] Example 70. The circuit of any one of Examples 68-69, wherein the signal detection circuit is configured to structure the NN code in a modular manner to allow for the introduction of new model parameters.

[0366] Example 71 The circuit of any one of Examples 68 to 70, wherein the signal detection circuit is configured to curate pulse waveform data to remove artifacts due to motion, scaling error, or signal compression error, or a combination thereof.

[0367] Example 72. The circuit of any one of Examples 65-71, wherein the signal detection circuit is configured to implement a calibration or anchor point.

[0368] Example 73 The circuit of example 72, wherein the signal detection circuit is configured to employ external data to improve the accuracy of the extracted blood pressure value.

[0369] Example 74 The circuit of Example 73, wherein the external data includes demographic information such as age, sex, height, and weight, and information regarding medical treatment such as high frequency oscillatory ventilation, circulatory assist devices, dialysis, birth weight, or gestational age, or any combination thereof.

[0370] Example 75. The circuit of any one of Examples 72-74, wherein the signal detection circuit is configured to take one or more inflatable cuff measurements at the start of sensor data collection as input to the model.

[0371] Example 76. The circuit of example 75, wherein the signal detection circuit is configured to take periodic cuff measurements as input to the model during the sensor data collection process.

[0372] Example 77. The circuit of any one of Examples 72-76, wherein the signal detection circuit is configured to employ inputs obtained from a prescribed starting schedule in which the sensor is applied and then used at multiple locations.

[0373] Example 78 A method for hemodynamic monitoring via a wearable device comprising a sensor circuit having at least one electrode, a conversion circuit for receiving a signal from the sensor circuit, converting the signal to a digital signal, and providing the digital signal to a signal detection circuit for processing the digital signal, the method including: detecting a capacitance signal by the sensor circuit with at least one electrode, the capacitance signal representing a pulse wave event or pressure and / or electric field modulation that may be due to changes in pressure or blood flow in a user's blood vessel; converting the detected capacitance signal by the conversion circuit into a digital signal indicative of the detected capacitance signal; providing the digital signal by the conversion circuit to the signal detection circuit; processing the digital signal representing the changes in capacitance over time to generate pulse waveform data by the signal detection circuit; correlating the pulse waveform data with various hemodynamic parameters by the signal detection circuit; processing the pulse waveform data by the signal detection circuit; and determining the hemodynamic parameters based on the pulse waveform data by the signal detection circuit.

[0374] Example 79 The method of Example 78, further comprising reducing motion artifacts with an accessory device.

[0375] Example 80 The method of Example 79, wherein the attachment device comprises a vibration dampening material for dampening vibration or motion artifacts.

[0376] Example 81 1. A method for measuring and processing one or more physiological parameters via a wearable device comprising: a sensor circuit comprising at least one electrode positioned near or on a user's skin; and a conversion circuit for receiving a signal from the sensor circuit, converting the signal to a digital signal, and providing the digital signal to a signal detection circuit for processing the digital signal. The method includes: sensing, by the sensor circuit, a capacitance signal with the at least one electrode, the capacitance signal representing a pulse wave event or a pressure and / or electric field modulation that may be due to a change in pressure or blood flow in a blood vessel of the user; converting, by the conversion circuit, the sensed capacitance signal into a digital signal indicative of the sensed capacitance signal; providing, by the conversion circuit, the digital signal to the signal detection circuit; processing, by the signal detection circuit, the digital signal representing the capacitance changes over time to generate pulse waveform data; correlating, by the signal detection circuit, the pulse waveform data with various hemodynamic parameters; processing, by the signal detection circuit; and implementing, by the signal detection circuit, a regression coefficient model based on the digital data received by the signal detection circuit that is associated with the sensed physiological parameter.

[0377] Example 82. The method of example 81, including determining, by the signal detection circuitry, a regression coefficient between the sensor data and the reference arterial line data using the pulse-by-pulse synchronized arterial and sensor data.

[0378] Example 83. The method of example 82, including employing, by the signal detection circuitry, the regression coefficient as a metric of sensor data quality.

[0379] Example 84: The method of any one of Examples 82-83, comprising: employing, by the signal detection circuit, a neural network trained on sensor data using regression coefficients as ground truth values; predicting, by the signal detection circuit, the likelihood that subsequent sensor data will be correlated to arterial line data; employing, by the signal detection circuit, the likelihood as a quality metric for filtering the sensor data to extract blood pressure values ​​from the pulse waveform data; and estimating, by the signal detection circuit, a confidence level for the extracted blood pressure values ​​based on the likelihood.

[0380] Example 85: The method of any one of Examples 81 to 84, including implementing a pulse waveform quality model based on the received sensor data by the signal detection circuit.

[0381] Example 86 The method of Example 85, including training, by the signal detection circuit, quality ratings from a rubric based on pulse waveform characteristics; visually evaluating, by the signal detection circuit, the pulse waveform data; and training, by the signal detection circuit, a convolutional neural network on the pulse waveform data with the ratings used as ground truth values.

[0382] Example 87: The method of any one of Examples 85-86, including filtering the sensor data by a signal detection circuit to extract a blood pressure value or providing a quality assessment of the subsequent sensor data to estimate a confidence level for the extracted value.

[0383] Example 88: The method of any one of Examples 85-87, including classifying the pulse waveform data into different canonical shapes by the signal detection circuitry to identify a waveform shape class for each new pulse waveform and determine whether a blood pressure value can be extracted from the pulse waveform and / or which model to use.

[0384] Example 89 The method of any one of Examples 81 to 88, including implementing, by the signal detection circuitry, a signal-to-noise ratio model based on the received sensor data.

[0385] Example 90. The method of example 89, including implementing, by the signal detection circuitry, the quality model based on a Fourier filter based on a Fourier transform of the received sensor data.

[0386] Example 91: The method of any one of Examples 89-90, including implementing a bandstop filter by the signal detection circuit to remove periodic noise, such as respiratory modes at lower frequencies and oscillatory ventilation noise at higher frequencies.

[0387] Example 92: The method of any one of Examples 89 to 91, comprising calculating the sensor data signal power by identifying, by the signal detection circuit, a primary frequency associated with the heart rate, and integrating, by the signal detection circuit, at the peak of the signal power along with multiple higher harmonics of the signal data.

[0388] Example 93 The method of Example 92, including integrating, by the signal detection circuit, the remaining data to determine a noise power value, and calculating, by the signal detection circuit, a ratio of signal power to noise power to produce a metric indicative of general quality sensor data.

[0389] Example 94: The method of any one of Examples 92-93, comprising: calculating a signal power to noise power ratio over a sliding data window by a signal detection circuit to determine a signal-to-noise ratio (SNR) as a function of time to filter / select received sensor data for further processing; and reconstructing the sensor signal data from the primary frequency employing higher harmonics by the signal detection circuit to derive a blood pressure value.

[0390] Example 95: The method of any one of Examples 81 to 94, including: implementing, by a signal detection circuit, a Kalman and particle filter model based on the received sensor data; processing, by the signal detection circuit, the sensor data through the Kalman and particle filter to separate the pulse waveform from other periodic signals and other artifacts due to electronic noise and movement; and separating, by the signal detection circuit, the pulse waveform data to extract a blood pressure value.

[0391] Example 96: A method for measuring and processing one or more physiological parameters via a wearable device comprising a sensor circuit comprising at least one electrode positioned near or on a user's skin, a conversion circuit for receiving a signal from the sensor circuit, converting the signal to a digital signal, and providing the digital signal to a signal detection circuit for processing the digital signal, the method comprising: sensing, by the sensor circuit, a capacitance signal with the at least one electrode, the capacitance signal representing movement, pressure, and / or electric field modulation that may be due to a pulse wave event, a change in pressure or blood flow in a blood vessel of the user, or movement of a part of the user's body; converting, by a conversion circuit, the sensed capacitance signal into a digital signal indicative of the sensed capacitance signal; providing, by the conversion circuit, the digital signal to a signal sensing circuit; processing, by the signal sensing circuit, the digital signal representing the change in capacitance over time to generate pulse waveform data; correlating, by the signal sensing circuit, the pulse waveform data with various hemodynamic parameters; processing, by the signal sensing circuit, the pulse waveform data; and implementing, by the signal sensing circuit, a model based on the digital data received by the signal sensing circuit that corresponds to the sensed physiological parameters.

[0392] Example 97 The method of Example 96, including implementing an artificial neural network by the signal detection circuitry and employing the artificial neural network by the signal detection circuitry to derive blood pressure and other hemodynamic values ​​from the normalized pulse waveform shape.

[0393] Example 98. The method of example 97, including employing, by the signal detection circuitry, a pre-trained convolutional neural network combined with a feature-based regression model.

[0394] Example 99. The method of any one of Examples 97-98, including structuring the neural network code in a modular manner to allow for the introduction of new model parameters by the signal detection circuit.

[0395] Example 100. The method of any one of Examples 97-99, including measuring arterial line data simultaneously with the sensor data by the signal detection circuit to derive a ground truth value for the sensor data on a pulse-by-pulse basis.

[0396] Example 101 The method of example 100, including curating the arterial line data by the signal detection circuitry to remove artifacts due to motion, scaling error, or signal compression error, or a combination thereof.

[0397] Example 102. The method of any one of Examples 100-101, including curating the arterial line data by the signal detection circuit to remove data in which the arterial line is under-attenuated or over-attenuated to improve the accuracy of the reported systolic and diastolic blood pressure values.

[0398] Example 103. The method of example 102, including automatically detecting the underdamped waveform by a signal detection circuit.

[0399] Example 104. The method of any one of Examples 96-103, including implementing a calibration or anchor point by a signal detection circuit.

[0400] Example 105 The method of Example 104, including employing external data to improve the accuracy of the blood pressure value extracted by the signal circuit, the external data including demographic information including age, sex, height, and weight, and information regarding medical treatment such as high frequency oscillatory ventilation, circulatory assist devices, dialysis, birth weight, or gestational age, or any combination thereof.

[0401] Example 106: The method of any one of Examples 104 to 105, including employing, by the signal detection circuitry, one or more inflatable cuff measurements at the start of sensor data collection as inputs to the model, and employing, by the signal detection circuitry, periodic cuff measurements as inputs to the model during the course of sensor data collection.

[0402] Example 107. The method of any one of Examples 104-106, including applying sensor data by the signal detection circuitry and then employing inputs derived from a prescribed starting plan used at the plurality of locations.

[0403] Terms illustrating orientation and direction, such as up / down, left / right, top / bottom, above / below, above / below, plumb, horizontal, and vertical, may be used herein to describe the relative positions of elements as shown in the figures. Similarly, because heating and cooling are relative terms in the art, it is understood that a heating source and a cooling source may be synonymous, given that the direction of temperature change can be controlled according to the desired temperature change. The terms are used for convenience of notation only, and it should be understood that in actual use, the disclosed structures may be oriented differently from those shown in the figures. Thus, the terms should not be construed in a limiting manner.

[0404] It may also be useful to understand the context / meaning of the following terms: The term "electrode" refers to or includes a conductive conductor. The term "sensor circuit" refers to or includes a circuit that includes the electrodes and a connection to a conversion circuit (e.g., having a sensor connector for the electrodes plugged or otherwise connected to the conversion circuit) and is used to detect or measure capacitance values ​​and / or capacitance changes via the electrodes and output them to the conversion circuit. The sensor circuit may further include various other elements, such as those shown in FIGS. 29A-29B and 30A-30B, and the sensor circuit may include a multi-layer structure including electrodes and various dielectric and conductive layers. The term "conversion circuit" refers to or includes a circuit that converts a change in a physical quality, such as a change in capacitance as provided by the sensor circuit, into an electrical signal. For example, the conversion circuit may include a capacitance-to-digital converter. The term “pulse wave event” refers to or includes a hemodynamic response and / or attribute caused by and / or indicative of a heartbeat (e.g., a contraction of the heart muscle) (e.g., a heartbeat or sound, a change in blood pressure or blood flow velocity, etc.). The term “pulse waveform” refers to or includes a signal or waveform produced by a pulse wave event. An exemplary pulse waveform includes an arterial pulse waveform, e.g., a waveform produced by the heart as it contracts and a wave travels along the arterial wall of the arterial tree. The term “electrical signal sensing circuit” refers to or includes a circuit used to sense hemodynamic or pulse wave events using an electrical signal from a conversion circuit. An exemplary electrical signal sensing circuit includes a microcontroller or other processing circuit, and an exemplary conversion circuit includes a capacitance-to-digital converter, although aspects are not so limited. The term “communication circuit” refers to or includes a circuit that outputs data to other external circuitry, which may include wireless or wired communication. An exemplary communication circuit includes a transceiver, although aspects are not so limited. The terms "hemodynamics" or "hemodynamic parameters" refer to or include parameters related to the flow of blood within the organs, vessels, and tissues of the body.Exemplary hemodynamic or hemodynamic parameters may include diastolic blood pressure, systolic blood pressure, arterial stiffness, and blood volume, among other parameters.

[0405] Various blocks, modules, or other circuits may be implemented to perform one or more of the operations and activities described herein and / or illustrated in the figures. For example, processes such as heating, etching, and deposition may be automated through the use of various circuits and associated machinery. In such contexts, various functions shown may be implemented using circuits that perform one or more of such or related operations / activities. In various aspects, hardwired control blocks may be used to minimize the area for such implementations when limited flexibility is sufficient. Alternatively and / or in addition, in certain of the above-described aspects, one or more modules are discrete logic circuits or programmable logic circuits constructed and arranged to implement such operations / activities.

[0406] By way of example, the specification describes and / or illustrates embodiments useful for implementing the claimed disclosure by circuitry that may be represented as or using terms such as various circuits, or blocks, modules, devices, systems, and / or other circuit type descriptions. Such circuits or circuits are used together with other elements (e.g., wristbands, external processing circuitry, etc.) to illustrate how a particular embodiment may be implemented in terms of form or structure, steps, functions, operations, activities, etc. For example, in certain of the above-described embodiments, one or more illustrated items in this context represent circuitry (e.g., discrete logic circuitry or (semi-)programmable circuitry) configured and arranged to implement the operation / activity as may be performed in the approach shown in the slide. In certain embodiments, the illustrated items represent one or more computer circuits (e.g., microcomputers or other CPUs) that are understood to include memory circuitry that stores code (a program implemented as a set / sets of instructions) that executes basic algorithms (e.g., monitoring pressure differentials and / or capacitance changes that may be attributable to pulse wave events) and / or determines hemodynamic parameters and / or more complex processes / algorithms as understood from known literature describing the specific parameter sensing. Specifically, the process / algorithm is implemented to perform the relevant steps, functions, operations, and activities as appropriate for a particular application. The specification may also make reference to adjectives that do not include any attributes of the structures ("first [type of structure]" and "second [type of structure]"), in which case the adjectives are used merely in English linguistic precedent to distinguish one such similarly named structure from another similarly named structure (e.g., "first electrode..." is interpreted as "electrode...").

[0407] Based on the above description and examples, those skilled in the art will readily recognize that various modifications and changes can be made to the various aspects without strictly adhering to the exemplary embodiments and applications shown and described herein. For example, a method as illustrated in the figures may include steps performed in a different order, or may include fewer or more steps, in one or more of the aspects retained herein. Such modifications do not depart from the true spirit and scope of the various aspects of the present disclosure, including those described in the claims.

Claims

1. a first dielectric layer having an inner surface and an outer surface; an electrically conductive layer located adjacent one of the inner surface or the outer surface of the first dielectric layer; an electrode having an outer surface, the outer surface of the electrode positioned proximate to the inner surface of the first dielectric layer, the outer surface of the electrode and the electrically conductive layer defining a gap.

2. The proximity sensor of claim 1 further comprising a foam layer.

3. The proximity sensor of claim 1 , further comprising a sealing layer disposed over the sensing surface.

4. the electrically conductive layer is located adjacent the inner surface of the first dielectric layer; The proximity sensor of claim 1 , further comprising a second dielectric layer disposed between the electrode and the electrically conductive layer, the outer surface of the electrode and the electrically conductive layer defining a gap.

5. The proximity sensor of claim 4 , wherein the second dielectric layer has a thickness of less than 3 μm.

6. The proximity sensor of claim 4 , wherein the second dielectric layer has a textured surface.

7. a first dielectric layer having an inner surface and an outer surface; an electrically conductive layer located adjacent one of the inner surface or the outer surface of the first dielectric layer; a sensing electrode located proximate the inner surface of the first dielectric layer, the sensing electrode having an inner surface and an outer surface, the outer surface of the sensing electrode located proximate the inner surface of the first dielectric layer, the outer surface of the sensing electrode and the electrically conductive layer defining a gap; a reference electrode disposed relative to the sensing electrode, the reference electrode being located proximate to the inner surface of the first dielectric layer, the reference electrode having an inner surface and an outer surface, the outer surface of the reference electrode being located proximate to the inner surface of the first dielectric layer, the outer surface of the reference electrode and the electrically conductive layer defining a gap.

8. The proximity sensor of claim 7 , wherein the reference electrode is disposed laterally relative to the sensing electrode, laminated relative to the sensing electrode, or mechanically separated from the sensing electrode.

9. The proximity sensor of claim 7 , further comprising a fifth dielectric layer disposed between the reference electrode and the first dielectric layer.

10. The proximity sensor of claim 7 , further comprising a sixth dielectric layer disposed between the sensing electrode and the first dielectric layer.

11. The proximity sensor of claim 7 , further comprising a substrate layer, the sense electrode and the reference electrode being located on opposite sides of the substrate layer.

12. a sensor element substrate comprising one of the proximity sensors defined in claims 1 to 11; at least one electrically conductive electrode lead disposed on the sensor element substrate; an electronic module; at least one electrically conductive pad disposed on the electronic module; and at least one elastically deformable, electrically conductive feature disposed on at least one of the at least one electrically conductive electrode lead or the at least one electrically conductive electrode pad, the at least one elastically deformable, electrically conductive feature positioned to make an electrical connection between the at least one electrically conductive lead and the at least one electrically conductive pad through the at least one elastically deformable, electrically conductive feature.

13. 1. A circuit for measuring a physiological parameter, the circuit comprising: a sensor circuit comprising a sensor element substrate comprising any one of the proximity sensors defined in claims 1 to 11, the sensor element substrate comprising at least one electrode, the sensor circuit being configured to monitor a capacitance signal between the at least one electrode and a user's skin, the capacitance signal being indicative of movement, pressure and / or electric field modulation that may be due to a pulse wave event, a change in pressure or blood flow in a blood vessel of the user, or movement of a body part of the user; a conversion circuit connected to the sensor circuit, the conversion circuit configured to convert the monitored capacitance signal into a digital signal indicative of the monitored capacitance signal; a signal detection circuit configured to receive the digital signal and determine at least one physiological parameter associated with the user.

14. 14. The circuit of claim 13, wherein the physiological parameters include blood pressure, systolic, diastolic, mean arterial pressure, pulse pressure, respiration rate, or combinations thereof, and their variability, or as time series values ​​and trends.

15. 14. The circuit of claim 13, wherein the signal detection circuit is configured to filter the sensor data for use in extracting a blood pressure value or providing a quality assessment for the subsequent sensor data to estimate a confidence level for the extracted value.

16. 1. A circuit for measuring a physiological parameter, the circuit comprising: a sensor circuit comprising a sensor element substrate comprising any one of the proximity sensors defined in claims 1 to 11, the sensor element substrate comprising at least one electrode, the sensor circuit being configured to monitor a capacitance signal between the at least one electrode and a user's skin, the capacitance signal being indicative of movement, pressure and / or electric field modulation that may be due to a pulse wave event, a change in pressure or blood flow in a blood vessel of the user, or movement of a body part of the user; a conversion circuit connected to the sensor circuit, the conversion circuit configured to convert the monitored capacitance signal into a digital signal indicative of the monitored capacitance signal; and a signal sensing circuit configured to implement a blood pressure or other hemodynamic or physiological model.

17. 17. The circuit of claim 16, wherein the signal sensing circuit is configured to convert the capacitance signal into a format that can be displayed on an external monitor and / or processed and stored on an external data system.

18. 17. The circuit of claim 16, wherein the signal detection circuit is configured to take inputs obtained from a prescribed starting schedule in which the sensor is applied and then used at multiple locations.

19. 1. A method for hemodynamic monitoring via a wearable device comprising: a sensor circuit comprising at least one electrode; a conversion circuit for receiving a signal from the sensor circuit, converting the signal to a digital signal, and providing the digital signal to a signal detection circuit for processing the digital signal, the method comprising: sensing, by the sensor circuitry, a capacitance signal by the at least one electrode, the capacitance signal representing pressure and / or electric field modulations that may result from pulse wave events or changes in pressure or blood flow within a blood vessel of the user; converting, by the conversion circuitry, the sensed capacitance signal into a digital signal indicative of the sensed capacitance signal; providing, by the conversion circuitry, the digital signal to the signal detection circuitry; The signal detection circuit processes the digital signal representing the change in capacitance over time to generate pulse waveform data. correlating the pulse waveform data with various hemodynamic parameters by the signal detection circuitry; processing the pulse waveform data by the signal detection circuit; determining, by the signal detection circuitry, a hemodynamic parameter based on the pulse waveform data.

20. 20. The method of claim 19, further comprising reducing motion artifacts with an accessory device.

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