Device for measuring a fluid meniscus
First Claim
1. A device for measuring a geometry of a fluid meniscus, comprising:
- a fluid chamber having a wall and comprising electrically conductive and electrically insulating fluids mutually immiscible and in contact with each other over the fluid meniscus, the wall and the fluid meniscus forming a contact angle;
a main electrowetting electrode in a main plane and a plurality of auxiliary electrowetting electrodes partially surrounding the fluid chamber in respective auxiliary planes;
a voltage source configured to provide voltages between the main electrowetting electrode and the plurality of auxiliary electrowetting electrodes at respective different frequencies, to thereby control the contact angle via the electrowetting effect; and
a measurement circuit configured to separately measure capacitances between the main electrowetting electrode and at least two of the plurality of auxiliary electrowetting electrodes, and including a multiplexer configured to demodulate a signal indicative of said respective capacitances using demodulation signals comprising the respective different frequencies thereby decomposing the signal into respective signal components,wherein dimensions of areas of the auxiliary electrowetting electrodes covered with the electrically conductive fluid change with the contact angle and indicate respective capacitances.
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Accused Products
Abstract
A device for measuring a geometry of a fluid meniscus includes a fluid chamber storing a first electrically conductive fluid and a second electrically insulating fluid. The fluids are mutually immiscible and define a fluid meniscus in between them. The device further includes a main electrowetting electrode and auxiliary electrowetting electrodes for controlling the geometry of the fluid meniscus. A voltage source provides a voltage between the main electrowetting electrode and the auxiliary electrowetting electrodes and a measurement circuit separately measures capacitances between the main electrowetting electrode and at least two of the auxiliary electrowetting electrodes. The measurement circuit includes a multiplexer for demodulating a signal indicative for the capacitances.
15 Citations
15 Claims
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1. A device for measuring a geometry of a fluid meniscus, comprising:
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a fluid chamber having a wall and comprising electrically conductive and electrically insulating fluids mutually immiscible and in contact with each other over the fluid meniscus, the wall and the fluid meniscus forming a contact angle; a main electrowetting electrode in a main plane and a plurality of auxiliary electrowetting electrodes partially surrounding the fluid chamber in respective auxiliary planes; a voltage source configured to provide voltages between the main electrowetting electrode and the plurality of auxiliary electrowetting electrodes at respective different frequencies, to thereby control the contact angle via the electrowetting effect; and a measurement circuit configured to separately measure capacitances between the main electrowetting electrode and at least two of the plurality of auxiliary electrowetting electrodes, and including a multiplexer configured to demodulate a signal indicative of said respective capacitances using demodulation signals comprising the respective different frequencies thereby decomposing the signal into respective signal components, wherein dimensions of areas of the auxiliary electrowetting electrodes covered with the electrically conductive fluid change with the contact angle and indicate respective capacitances. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for measuring a geometry of a fluid meniscus comprising acts of:
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providing electrically conducting and electrically insulating mutually immiscible fluids in a fluid chamber having a wall, the wall and the fluid meniscus forming a contact angle; providing a main electrowetting electrode in a main plane and a plurality of auxiliary electrowetting electrodes partially surrounding the fluid chamber in respective auxiliary planes; controlling the contact angle via the electrowetting effect by providing voltages at respective different frequencies between the main electrowetting electrode and the plurality of auxiliary electrowetting electrodes; measuring by a measurement circuit comprising a multiplexer capacitances between the main electrowetting electrode and at least two of the a plurality of auxiliary electrowetting electrodes; and demodulating a signal indicative of said respective capacitances using demodulation signals comprising the respective different frequencies thereby decomposing the signal into respective signal components, wherein dimensions of areas of the auxiliary electrowetting electrodes covered with the electrically conductive fluid change with the contact angle and indicate respective capacitances. - View Dependent Claims (15)
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Specification