Using electrical resistance to estimate force on an electrode during temperature changes
AssigneeSynaptics Incorporated
InventorTom Vandermeijden
Life of this patent
Estimating the term…
Abstract
A processing system includes sensor circuitry and processing circuitry. The sensor circuitry is configured to, using the sensor electrodes, obtain capacitive measurements of a sensing region, and obtain a resistance measurement of the sensing region. The processing circuitry is coupled to the sensor circuitry. The processing circuitry is configured to determine a location of an input object using the capacitive measurements of the sensing region and determine a force value based on the resistance measurement and the location of the input object. Determining the force value mitigates a temperature variation of the sensing region affecting the resistance measurement. The processing circuitry is further configured to report the force value.
Claims15
A processing system, comprising:
- sensor circuitry configured to, using a plurality of sensor electrodes:
- obtain a plurality of capacitive measurements of a sensing region;
- and
- obtain a resistance measurement of the sensing region;
- and
- processing circuitry coupled to the sensor circuitry, wherein the processing circuitry is configured to:
- determine a location of an input object using the plurality of capacitive measurements of the sensing region, wherein the location corresponds to a virtual button,
- acquire a first resistance measurement using a subset of the plurality of sensor electrodes in a region that excludes the virtual button,
- determine a force value, the force value based on:
- a rate of change in the first resistance measurement during a first time period, and
- intermediate force values, the intermediate force values based on a second resistance measurement, the second resistance measurement to occur during a second time period, the second time period after the first time period,
- wherein determining the force value mitigates a temperature variation of the sensing region affecting the resistance measurement;
- and
- report the force value.
A method comprising:
- measuring first resistance values of one or more electrodes during a first time interval;
- calculating a first rate of change in the first resistance values;
- measuring second resistance values of one or more electrodes during a second time interval, the second time interval after the first time interval;
- calculating intermediate force values based on the second resistance values, the intermediate force values reflective of a force applied to a surface;
- calculating a rate of change of the intermediate force values;
- and
- determining a state variable based on the rate of change of the intermediate force values, wherein the state variable corresponds to a force applied state or a no force applied state based on whether the rate of change of the intermediate force values is a positive value or whether the rate of change of the intermediate force values is a negative value, respectively.
An apparatus, comprising:
- a plurality of sensor electrodes;
- and
- a processing system, configured to:
- measure first resistance values of one or more electrodes of the plurality of electrodes during a first time interval;
- calculate a first rate of change in the first resistance values;
- measure second resistance values of one or more electrodes of the plurality of electrodes during a second time interval, the second time interval after the first time interval;
- calculate intermediate force values based on the second resistance values, the intermediate force values reflective of a force applied to a surface;
- calculate a rate of change of the intermediate force values;
- and
- determine a state variable based on the rate of change of the intermediate force values, wherein the state variable corresponds to a force applied state or a no force applied state based on whether the rate of change of the intermediate force values is a positive value or whether the rate of change of the intermediate force values is a negative value, respectively.
Dependencies are inferred from the claim text.