US 12,277,290 B2
Touchpad force calculation using no-touch capacitance
Ahia Peretz, Elkana (IL); On Haran, Kfar Saba (IL); and Lior Zagiel, Tel Aviv (IL)
Assigned to Microsoft Technology Licensing, LLC, Redmond, WA (US)
Filed by Microsoft Technology Licensing, LLC, Redmond, WA (US)
Filed on Sep. 8, 2023, as Appl. No. 18/463,572.
Prior Publication US 2025/0085807 A1, Mar. 13, 2025
Int. Cl. G06F 3/041 (2006.01)
CPC G06F 3/0418 (2013.01) [G06F 2203/04105 (2013.01); G06F 2203/04107 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for estimating a force F exerted on a touchpad in a computing device, the touchpad comprising a printed circuit board (PCB) comprising a capacitive force sensing electrode and a shielded electrode located between a first shielding layer and a second shielding layer to substantially isolate the shielded electrode from changes in capacitance caused by movement of the PCB, the method comprising:
determining that the touchpad is not being touched;
at least on condition of determining that the touchpad is not being touched, calculating a no-touch capacitance value of the PCB;
after calculating the no-touch capacitance value, determining that the touchpad is being touched;
while the touchpad is being touched, calculating a measured change in capacitance by subtracting the no-touch capacitance value from a touch-based capacitance value;
calculating an environmental change in capacitance at the shielded electrode;
using the environmental change in capacitance to adjust the measured change in capacitance to an adjusted measured change in capacitance; and
at least on condition that the touchpad is being touched, using the adjusted measured change in capacitance to estimate the force F exerted on the touchpad.