US 12,449,941 B2
Apparatus and method for capacitive touch detection
Wilhelmus Van Lier, St Asaph (GB); and Henricus Derckx, St Asaph (GB)
Assigned to Touch Biometrix B.V., Weert (NL)
Appl. No. 18/572,957
Filed by Touch Biometrix B.V., Weert (NL)
PCT Filed Jun. 30, 2022, PCT No. PCT/GB2022/051691
§ 371(c)(1), (2) Date Dec. 21, 2023,
PCT Pub. No. WO2023/275559, PCT Pub. Date Jan. 5, 2023.
Claims priority of application No. 2109468 (GB), filed on Jun. 30, 2021.
Prior Publication US 2024/0288972 A1, Aug. 29, 2024
Int. Cl. G06F 3/044 (2006.01); G01D 5/24 (2006.01)
CPC G06F 3/044 (2013.01) [G01D 5/24 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method comprising:
providing a reference current (Ibias) through a sense TFT of a sensing element to operate the sensing element, the sensing element comprising the sense TFT having a gate connection connected to a sensing electrode;
providing a reference voltage (Vbias) at the gate connection to obtain a reference sample voltage (Vcap) from a source connection of the sense TFT;
providing, at the gate connection, an indicator voltage (Vgate) dependent upon a parameter to be sensed whilst the reference current (Ibias) continues to be provided through the sense TFT to obtain a sensing voltage from the source connection of the sense TFT; and
sensing the parameter based on the difference between the sensing voltage (Vs) and the reference sample voltage (Vcap),
wherein the parameter comprises capacitance of the sensing electrode or accumulated charge on the sensing electrode.