US 12,443,310 B2
Touch-sensitive apparatus with improved noise immunity and method
Trond Jarle Pedersen, Trondheim (NO)
Assigned to TouchNetix AS, Trondheim (NO)
Appl. No. 18/718,189
Filed by TouchNetix AS, Trondheim (NO)
PCT Filed Dec. 20, 2022, PCT No. PCT/EP2022/086921
§ 371(c)(1), (2) Date Jun. 10, 2024,
PCT Pub. No. WO2023/118091, PCT Pub. Date Jun. 29, 2023.
Claims priority of application No. 2118649 (GB), filed on Dec. 21, 2021.
Prior Publication US 2025/0053261 A1, Feb. 13, 2025
Int. Cl. G06F 3/041 (2006.01); G01D 5/24 (2006.01); G06F 3/044 (2006.01)
CPC G06F 3/0418 (2013.01) [G01D 5/24 (2013.01); G06F 3/04166 (2019.05); G06F 3/0446 (2019.05)] 13 Claims
OG exemplary drawing
 
1. A touch-sensitive apparatus for sensing the presence of an object relative to a touch-sensitive surface using capacitance measurements, the apparatus comprising:
an electrode array comprising a plurality of electrodes, the electrode array providing the touch-sensitive surface;
a signal generating module for generating a time-varying drive signal to be applied to the electrode array;
a differential amplifier comprising:
a first input configured to receive a time-varying sensor signal from an electrode of the electrode array, the sensor signal indicative of a capacitive coupling associated with the electrode of the electrode array;
a second input configured to receive a time-varying reference signal;
a first output configured to output a first output signal from the differential amplifier based on a difference between the time-varying sensor signal and the time-varying reference signal; and
control circuitry configured to determine the presence of an object,
wherein the apparatus further comprises a subtractor for subtracting a signal from the first output signal from the differential amplifier to generate a subtracted signal,
wherein the control circuitry is configured to receive a signal based on the subtracted signal and to determine the presence of an object based on the received signal.