Patent ID: 9109876
Filing Date: 2015-08-18
Classification: G01B,G01R,G02B

Abstract:
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.