Multi-touch capacitive sensing surface

A touch-sensitive input device, comprising:

• a first electrode disposed in a first plane;
• a second electrode disposed in a second plane substantially parallel to the first plane, the second electrode extending substantially perpendicular to the first electrode;
• at least one of a flexible dielectric material or an air gap spacing the first electrode from the second electrode, the first electrode and the second electrode configured to determine a first capacitance associated with a conductor contacting a surface of the touch-sensitive input device;
• and
• a third electrode disposed in a third plane substantially parallel to the first plane, the third electrode extending substantially parallel to the first electrode and being spaced from the first electrode by the at least one of the flexible dielectric material or the air gap, the second electrode and the third electrode configured to determine a second capacitance substantially simultaneously with the first capacitance, wherein:
• one of the first capacitance or the second capacitance is determinable based, at least in part, on a self-capacitance measurement;
• the other of the first capacitance and the second capacitance is determinable based, at least in part, on a mutual-capacitance measurement;
• and
• the contact between the conductor and the surface of the touch-sensitive input device is classifiable as one of an inadvertent contact or an intentional contact based, at least in part, on the first capacitance, the second capacitance, a pressure threshold value associated with an inadvertent contact measured using one of the first capacitance and the second capacitance and a location threshold value associated with known input mechanisms measured using the other of the first capacitance and the second capacitance.

A method, comprising:

• determining a first capacitance associated with a conductor contacting a surface of a touch-sensitive input device, the touch-sensitive input device being external to an associated computing device, the first capacitance being determined by a first electrode disposed in a first plane and a second electrode disposed in a second plane substantially parallel to the first plane, the first electrode extending substantially perpendicular to the second electrode and being spaced from the second electrode by at least one of a flexible dielectric material or an air gap;
• determining a second capacitance associated with the conductor contacting the surface of the touch-sensitive input device, the second capacitance being determined by the second electrode and a third electrode disposed in a third plane substantially parallel to the first plane, the third electrode extending substantially parallel to the first electrode and being spaced from the first electrode by the at least one of the flexible dielectric material or the air gap;
• determining one of the first capacitance or the second capacitance based at least in part on a self-capacitance measurement;
• determining the other of the first capacitance and the second capacitance based at least in part on a mutual-capacitance measurement;
• directing information indicative of the first capacitance and the second capacitance from the input device to a processor operably connected to the input device;
• determining, with the processor, a pressure applied to the surface of the touch-sensitive input device by the conductor based on the information indicative of the first capacitance;
• determining a location on the surface of the touch-sensitive input device based on the information indicative of the second capacitance substantially simultaneously with the first capacitance;
• determining a first difference between the first capacitance and a respective baseline and a second difference between the second capacitance and the respective baseline;
• and
• classifying contact between the conductor and the surface of the touch-sensitive input device as being one of an inadvertent contact or an intentional contact based at least in part on the first difference, the second difference, and a location difference threshold value associated with known input mechanisms.