Systems, articles, and methods for capacitive electromyography sensors

Abstract

Systems, articles, and methods for improved capacitive electromyography (“EMG”) sensors are described. The improved capacitive EMG sensors include one or more sensor electrode(s) that is/are coated with a protective barrier formed of a material that has a relative permittivity εr of about 10 or more. The protective barrier shields the sensor electrode(s) from moisture, sweat, skin oils, etc. while advantageously contributing to a large capacitance between the sensor electrode(s) and the user's body. In this way, the improved capacitive EMG sensors provide enhanced robustness against variations in skin and/or environmental conditions. Such improved capacitive EMG sensors are particularly well-suited for use in wearable EMG devices that may be worn by a user for an extended period of time and/or under a variety of skin and/or environmental conditions. A wearable EMG device that provides a component of a human-electronics interface and incorporates such improved capacitive EMG sensors is described.

1 . A method of fabricating an electromyography (“EMG”) sensor, the method comprising:
 forming at least a portion of at least one circuit on a first surface of a substrate; 
 forming a first electrode on a second surface of the substrate, the second surface of the substrate opposite the first surface of the substrate across a thickness of the substrate, wherein the first electrode comprises a first electrically conductive plate; 
 forming at least a first electrically conductive pathway through the substrate that communicatively couples the first electrode and the at least a portion of at least one circuit; 
 forming a second electrode on the second surface of the substrate, wherein the second electrode comprises a second electrically conductive plate; 
 forming at least a second electrically conductive pathway through the substrate that communicatively couples the second electrode and the at least a portion of at least one circuit. 
 
     
     
         2 . The method of  claim 1  wherein forming a first electrode on a second surface of the substrate includes forming a first sensor electrode on the second surface of the substrate. 
     
     
         3 . The method of  claim 2  wherein forming a second electrode on a second surface of the substrate includes forming a ground electrode on the second surface of the substrate. 
     
     
         4 . The method of  claim 2  wherein forming a second electrode on a second surface of the substrate includes forming a second sensor electrode on the second surface of the substrate. 
     
     
         5 . The method of  claim 4 , further comprising:
 forming a ground electrode on the second surface of the substrate, wherein the ground electrode comprises a third electrically conductive plate; and   forming at least a third electrically conductive pathway through the substrate that communicatively couples the ground electrode and the at least a portion of at least one circuit.   
     
     
         6 . The method of  claim 1  wherein forming a first electrode on a second surface of the substrate and forming a second electrode on the second surface of the substrate include forming the first electrode and the second electrode coplanar to one another on the second surface of the substrate. 
     
     
         7 . The method of  claim 1  wherein forming at least a portion of at least one circuit on a first surface of a substrate includes forming, on the first surface of the substrate, at least a portion of at least one circuit selected from a group consisting of: an amplification circuit, a filtering circuit, and an analog-to-digital conversion circuit.