Miniature electric field detector
Inventors
Bickford, James A. • Wheeler, Jesse J. • Golmon, Stephanie Lynne
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Assignees
Charles Stark Draper Laboratory Inc
Member
DraperDraper is an independent nonprofit engineering innovation company with a legacy spanning over 90 years, dedicated to delivering transformative solutions for national security, prosperity, and global challenges. Renowned for its pioneering work in guidance, navigation, and control (GN&C) systems, Draper partners with government, industry, and academia to engineer advanced technologies in space, defense, biotechnology, and electronic systems. The company leverages multidisciplinary expertise, digital engineering, and a collaborative approach to provide field-ready prototypes, mission-critical systems, and innovative research. Draper’s mission is to ensure the nation's security and prosperity by delivering sustainable, cutting-edge solutions that address the toughest problems of today and tomorrow, while fostering an inclusive and diverse workforce. Draper also invests in the next generation of innovators through robust educational programs, including internships, co-ops, and the Draper Scholars Program, integrating academic research with real-world problem-solving.
Draper is an independent nonprofit engineering innovation company with a legacy spanning over 90 years, dedicated to delivering transformative solutions for national security, prosperity, and global challenges. Renowned for its pioneering work in guidance, navigation, and control (GN&C) systems, Draper partners with government, industry, and academia to engineer advanced technologies in space, defense, biotechnology, and electronic systems. The company leverages multidisciplinary expertise, digital engineering, and a collaborative approach to provide field-ready prototypes, mission-critical systems, and innovative research. Draper’s mission is to ensure the nation's security and prosperity by delivering sustainable, cutting-edge solutions that address the toughest problems of today and tomorrow, while fostering an inclusive and diverse workforce. Draper also invests in the next generation of innovators through robust educational programs, including internships, co-ops, and the Draper Scholars Program, integrating academic research with real-world problem-solving.
Publication Number
US-12089941-B2
Publication Date
2024-09-17
Expiration Date
Abstract
According to various aspects, a sensor system is provided comprising a first substrate configured to be coupled to a user, an electric field detector to detect a user electric field and comprising a second substrate, a proof mass positioned above the second substrate, one or more electrodes coupled to the second substrate, and a control circuit coupled to the one or more electrodes, the control circuit being configured to determine a change in capacitance between the proof mass and each electrode responsive to torsional movement of the proof mass responsive to the electric field, and a controller coupled to the first substrate and being configured to receive, from the detector, information indicative of each change in capacitance between the proof mass and each electrode, and determine, based on the information, characteristics of the electric field in at least two dimensions.
Core Innovation
A sensor system comprising a first substrate configured to be coupled to a user and an electric field detector coupled to the first substrate, the electric field detector comprising a second substrate, a proof mass positioned above the second substrate, one or more electrodes coupled to the second substrate, and a control circuit configured to determine a respective change in capacitance between the proof mass and each respective electrode responsive to torsional movement of the proof mass in response to the electric field. A controller coupled to the first substrate and to the electric field detector is configured to receive, from the electric field detector, information indicative of each respective change in capacitance and determine, based on that information, characteristics of the electric field in at least two dimensions.
The invention addresses measurement of faint bio-electrical fields generated by the human body, which the background explains are often faint and attenuate with distance and are challenging to accurately measure with compact sensors. The patent positions the described detector as an approach to directly measure bio-electrical signals (for example, muscle or heart electric fields) by transducing induced torques on a charged or polarizable proof mass into capacitance changes, enabling determination of direction, phase, and magnitude of electric fields without necessarily relying on conventional multi-electrode ECG arrangements.
Claims Coverage
Independent claims identified: three independent claims (claim 1, claim 4, and claim 18). The following inventive features are extracted from those independent claims.
Sensor system with proof mass capacitance readout
A sensor system comprising a first substrate configured to be coupled to a user; an electric field detector coupled to the first substrate and comprising a second substrate, a proof mass positioned above the second substrate, one or more electrodes coupled to the second substrate, and a control circuit configured to determine a respective change in capacitance between the proof mass and each respective electrode of the one or more electrodes responsive to torsional movement of the proof mass in response to the electric field; and a controller configured to receive information indicative of each respective change in capacitance and determine characteristics of the electric field in at least two dimensions.
Selective dielectric dipole polarization
An electric dipole coupled to the proof mass, wherein the electric dipole includes a dielectric material, and wherein the control circuit is configured to selectively polarize the dielectric material along a first polarization axis and a second polarization axis, the first polarization axis being orthogonal to the second polarization axis.
Proof mass rotation about orthogonal torque axes
A proof mass configured to rotate about a first torque axis orthogonal to a polarization axis responsive to a first vector component of the electric field aligned with a first electric field axis, and rotate about a second torque axis orthogonal to the polarization axis responsive to a second vector component aligned with a second electric field axis, wherein the second torque axis is parallel to the first electric field axis and the first torque axis is parallel to the second electric field axis (as recited in an independent sensor system claim).
Multi-set electrode capacitance sensing for orthogonal torques
A plurality of electrodes including a first set and a second set, with a control circuit configured to determine a first change in capacitance between the proof mass and the first set responsive to torsional movement about a first torque axis and a second change in capacitance between the proof mass and the second set responsive to torsional movement about a second torque axis orthogonal to the first torque axis (as recited in an independent electric field detector claim).
Electric field detector device with orthogonal torque readout
An electric field detector comprising: a substrate; a proof mass positioned above the substrate; a plurality of electrodes coupled to the substrate including a first set and a second set; and a control circuit configured to determine a first change in capacitance between the proof mass and the first set responsive to torsional movement about a first torque axis and a second change in capacitance between the proof mass and the second set responsive to torsional movement about a second torque axis orthogonal to the first torque axis, and an electric dipole that includes a dielectric material selectively polarizable along orthogonal axes.
The independent claims cover a user-coupled sensor system and a standalone electric field detector that transduce torsional motion of a proof mass into capacitance changes using multiple electrode sets, and that employ a coupled electric dipole (including a selectively polarizable dielectric) to enable multi‑axis electric field characterization.
Stated Advantages
Improvement in signal-to-noise ratio and volume to directly measure bio-electrical signals such as brain activity or muscular activity.
Capability to meet performance requirements for compact electric field detection without contacting the head or body, offering improved user comfort and convenience.
Low noise at compact size and low production cost (the patent cites example targets: low noise, compact volume, and low production cost).
Ability to determine characteristics of the electric field in multiple or three orthogonal dimensions using multi-axis detection or selectively polarized dielectric dipoles.
Identification and mitigation of motion artifacts by using auxiliary sensors and controller-based compensation.
Documented Applications
Detecting bio-physical signals generated by the body, including electric fields of muscles, the heart, and the brain (electric field encephalography).
Integration into an adhesive patch removably coupled to a patient's body to detect electrical fields from proximate muscles (for example, on a patient's chest to detect heart fields or on legs to detect skeletal muscle fields).
Integration into clothing, compressive bands, watch bands, straps, headsets, or a helmet-like cap for arrayed spatial sensing (for example, a headset array to detect brain signals).
Integration into catheter systems or implantable devices to measure intracardiac signals or for implantable sensing.
Distributed sensing systems with implantable and external portions exchanging power and information for internal biological electric field measurement.
Clinical and diagnostic applications referenced include enhancing diagnostics and treatment for neurological and psychiatric conditions and other clinical applications (for example, ADHD, autism, dyslexia, depression, insomnia, impulsivity, anxiety, pain management, mental health treatment, epilepsy, and dementia).
Muscle monitoring applications, including monitoring skeletal muscles such as calves and quadriceps and other muscles.
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