US 11,989,968 B2
Fingerprint sensing system with current control
Ping-Liang Chen, Hsinchu (TW); and Andreas Larsson, Herrljunga (SE)
Assigned to FINGERPRINT CARDS ANACATUM IP AB, Gothenburg (SE)
Appl. No. 18/259,290
Filed by FINGERPRINT CARDS ANACATUM IP AB, Gothenburg (SE)
PCT Filed Feb. 8, 2022, PCT No. PCT/SE2022/050136
§ 371(c)(1), (2) Date Jun. 26, 2023,
PCT Pub. No. WO2022/173351, PCT Pub. Date Aug. 18, 2022.
Claims priority of application No. 2150153-1 (SE), filed on Feb. 12, 2021.
Prior Publication US 2024/0062574 A1, Feb. 22, 2024
Int. Cl. G06V 40/13 (2022.01); G11C 11/419 (2006.01)
CPC G06V 40/1306 (2022.01) [G11C 11/419 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A fingerprint sensing system for sensing a finger surface of a finger, comprising:
a plurality of conductive selection lines arranged in parallel to each other;
a plurality of conductive read-out lines arranged in parallel to each other and crossing the selection lines;
selection circuitry coupled to each selection line in the plurality of selection lines, and controllable to provide a selection signal on at least one selected selection line in the plurality of selection lines;
current providing circuitry coupled to the read-out lines and controllable to generate a current in at least one of the read-out lines; and
a plurality of pixel elements, each being formed at a respective intersection between a selection line in the plurality of selection lines and a read-out line in the plurality of read-out lines,
each pixel element in the plurality of pixel elements comprising:
a sensing element responsive to a property indicative of a distance between the sensing element and the finger surface to provide an output indicating a sensed value of the property; and
a sensing signal providing element coupled to the sensing element, the selection line and the read-out line, the sensing signal providing element being configured to, in response to the selection signal being provided on the selection line, control the potential on the read-out line to a sensing potential being dependent on the output provided by the sensing element,
wherein the fingerprint sensing system further comprises:
operation control circuitry coupled to the selection circuitry and to the current providing circuitry, and configured to, for each pixel element in the plurality of pixel elements:
provide a first control signal to the selection circuitry for controlling the selection circuitry to provide the selection signal on the selection line coupled to the sensing signal providing element of the pixel element; and
provide a second control signal to the current providing circuitry to generate a current in the read-out line coupled to the sensing signal providing element of the pixel element.