Mechanical Deflection Compensation for a Capacitive Touch Input Device

A method for monitoring mechanical deflection of a contact layer of a touch sensitive device, the method comprising:

• measuring output signals associated with a multi-layer electrode pattern of the touch sensitive device generated in response to contact on the contact layer;
• identifying at least a first electrode, of a first electrode layer of the multi-layer electrode pattern, positioned at an approximate location of contact on the contact layer;
• selecting an output signal from the measured output signals, wherein the output signal is associated with at least one other electrode of the first electrode layer that is separated from the first electrode by a distance, and wherein the output signal corresponds to a deflection capacitance;
• and
• determining a mechanical deflection of the contact layer caused by the contact, based on the deflection capacitance.

A system for monitoring mechanical deflection of a contact layer on a touch sensitive device, the system comprising:

• one or more analog-to-digital converters configured to measure output signals associated with a multi-layer electrode pattern, wherein the output signals occur in response to contact on the contact layer, and a first electrode layer of the multi-layer electrode pattern includes a first electrode and at least one other electrode that is separated from the first electrode by a distance;
• and
• a processor configured to:
• identify a relative location of the first electrode in response to contact being made with the contact layer approximately at the first electrode;
• select an output signal from the measured output signals, wherein the output signal is associated with the at least one other electrode of the first layer of electrodes, and wherein the output signal corresponds to a deflection capacitance;
• and
• determine a mechanical deflection of the contact layer caused by the contact, based on the deflection capacitance.

A non-transitory computer readable storage medium having stored therein data representing instructions executable by a programmed processor for monitoring mechanical deflection of a contact layer on a touch sensitive device, the instructions comprising:

• measuring output signals associated with a multi-layer electrode pattern of the touch sensitive device generated in response to contact on the contact layer;
• identifying at least a first electrode of a first electrode layer of the multi-layer electrode pattern, positioned at an approximate location of contact on the contact layer;
• selecting an output signal from the measured output signals, wherein the output signal is associated with at least one other electrode of the first layer of electrodes that is separated from the first electrode by a distance, and wherein the output signal corresponds to a deflection capacitance;
• determining a mechanical deflection of the contact layer caused by the contact, based on the deflection capacitance.