Printed hygroscopic electrodes for low-cost capacitive relative humidity sensors
AssigneePalo Alto Research Center Incorporated
InventorsAdrien Pierre, Sean Emerson Doris, David Eric Schwartz
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Abstract
A capacitive relative humidity sensor includes a first electrode and a second electrode, where at least the one of the electrodes is a water-permeable electrode. The electrodes act in conjunction with a water-sensitive hygroscopic dielectric material. The design enables low-cost and simple fabrication of fast-responding and stable relative humidity sensors using digital fabrication techniques.
Claims19
A method of forming a capacitive relative humidity sensor comprising:
- optionally pre-treating a water absorptive dielectric layer;
- depositing a first electrode on at least a portion of a surface of the water absorptive dielectric layer;
- and
- depositing a second electrode on at least a portion of another surface of the water absorptive dielectric layer, wherein at least one of the first electrode and the second electrode is comprised of a water permeable material;
- wherein a geometric dimension of the water absorptive dielectric layer changes with humidity, said changes of the geometric dimension causing changes in capacitance between the first electrode and the second electrode.
A method of forming a capacitive relative humidity sensor comprising:
- depositing a first electrode on at least a portion of a substrate;
- depositing a water absorptive dielectric layer on at least a portion of the first electrode;
- optionally pre-treating the water absorptive dielectric layer;
- and
- depositing a second electrode on at least a portion of the water absorptive dielectric layer, wherein the second electrode layer is made of a water permeable material;
- wherein a geometric dimension of the water absorptive dielectric layer changes with humidity, said changes in the geometric dimension causing changes in capacitance between the first electrode and the second electrode.
A capacitive relative humidity sensor, comprising:
- a water absorptive dielectric layer having a first surface and a second surface;
- a first electrode positioned in contact with at least a portion of the first surface of the water absorptive dielectric layer;
- and
- a second water-permeable electrode positioned in contact with at least a portion of the second surface of the of the water absorptive dielectric layer;
- wherein a geometric dimension of the water absorptive dielectric layer changes in response to humidity, said changes in the geometric dimension causing changes in capacitance between the first electrode and the second electrode.
A capacitive relative humidity sensor, comprising:
- a water absorptive dielectric layer having a first surface and a second surface;
- a first electrode positioned in contact with at least a portion of the first surface of the water absorptive dielectric layer;
- a second electrode positioned in contact with at least a portion of the second surface of the of the water absorptive dielectric layer;
- and
- a non-water absorptive dielectric positioned between at least a portion of one of the first and second surfaces of the water absorptive dielectric and one of the first and second electrodes;
- wherein at least one of the first and second electrodes is water-permeable;
- and
- wherein, in response to humidity, the water absorptive dielectric layer exhibits at least one of (i) changes in at least one of its geometric dimensions and (ii) changes in its relative permittivity, said changes causing changes in capacitance between the first electrode and the second electrode.
Dependencies are inferred from the claim text.