System and method for detecting and characterizing force inputs on a surface

A method for detecting and characterizing touch inputs comprising:

• during a first scan cycle:
• reading a first set of touch values from a touch sensor;
• and
• interpreting absence of inputs over a tactile surface, arranged over the touch sensor, based on the first set of touch values;
• generating a first touch image indicating absence of inputs on the tactile surface;
• during a second scan cycle succeeding the first scan cycle:
• reading a second set of touch values from the touch sensor;
• and
• interpreting presence of a second input over the tactile surface based on the second set of touch values;
• generating a second touch image indicating presence of the second input over the tactile surface;
• during a third scan cycle succeeding the second scan cycle:
• reading a set of force values from an array of sense electrodes adjacent the touch sensor;
• and
• interpreting a force magnitude of the second input based on the set of force values;
• and
• generating a third touch image indicating the force magnitude of the second input on the tactile surface.

A system comprising:

• a substrate;
• a tactile surface arranged over the substrate;
• a touch sensor arranged below the tactile surface;
• a first shield electrode coupled to the touch sensor;
• an array of sense electrodes arranged on the substrate;
• and
• a controller, coupled to the touch sensor and the array of sense electrodes and configured to, during a first scan cycle:
• at a first time, release the first shield electrode from a virtual reference potential;
• read a first set of touch values over the tactile surface from the touch sensor;
• at a second time following the first time, drive the first shield electrode to a virtual reference potential;
• read a first set of force values over the tactile surface from the array of sense electrodes;
• interpret a first location of a first input over the tactile surface based on the first set of touch values;
• interpret a first force magnitude of the first input over the tactile surface based on the first set of force values;
• interpret a second location of a second input over the tactile surface based on the first set of touch values;
• and
• interpret a second force magnitude for the second input over the tactile surface based on the first set of force values.

A system for detecting and characterizing touch inputs comprising:

• a substrate;
• an array of drive electrode and sense electrode pairs arranged on the substrate;
• a touch sensor arranged over the substrate;
• a force sensitive material in contact with the array of drive electrode and sense electrode pairs, the force sensitive material exhibiting variations in local resistance across drive electrode and sense electrode pairs in the array of drive electrode and sense electrode pairs, responsive to local variations in force applied over the substrate;
• and
• a controller coupled to the array of sense electrodes and the touch sensor and configured to:
• during a first scan period within a first sampling period, read a first set of force values from the array of sense electrodes;
• during a second scan period within the first sampling period, read a first set of touch values from the touch sensor;
• and
• transform the first set of force values and the first set of touch values into a touch image, the touch image representing locations and force magnitudes of a set of inputs over the substrate.