Droplet-based capacitive pressure sensor

摘要

A pressure sensing apparatus which utilizes an electrolytic droplet retained between a first and second sensing electrode within a housing. Contact between the electrolyte droplet and the electrodes form electric double layers (EDL) having interfacial EDL capacitance proportional to interface contact area which varies in response to mechanical pressure applied to deform exterior portions of the housing. The electrolyte contains a sufficient percentage of glycerol to prevent evaporative effects. Preferably, the sensing electrodes are modified with depressions, hydrophilic and/or hydrophobic portions to increase central anchoring of the electrolyte droplet within the housing. The inventive pressure sensor provides high sensitivity and resolution which is beneficial to numerous applications, and is particularly well-suited for medical sensing applications.

主权项

1. A droplet-based capacitive sensor apparatus, comprising:
a sensing chamber within an interior volume of a housing having a first and second substrate between which are disposed a substrate separation structure maintaining a periphery of said first and second substrates at a fixed separation distance to form said sensing chamber; wherein at least one of said first or second substrates is flexible; a conductive surface coating on the interior surfaces of said first substrate and said second substrate to form a first electrode and a second electrode; and an electrolyte droplet retained in said sensing chamber in contact with said first and second electrodes and leaving a gap between said electrolyte droplet and said substrate separation structure; wherein contact between said electrolyte droplet and said first and second electrodes form electric double layers (EDL) having interfacial EDL capacitance proportional to interface contact area which varies in response to mechanical pressure applied to deform at least one of said substrates which is flexible.