公开(公告)号：US09881197B2

公开(公告)日：2018-01-30

申请号：US15591601

申请日：2017-05-10

Applicant: Fingerprint Cards AB

Inventor： Fredrik Ramberg ,  Hans Thörnblom

IPC: G06K9/00

CPC classification number: G06K9/0002

Abstract: A capacitive fingerprint sensing device and method therein for noise detection are disclosed. The fingerprint sensing device comprises a plurality of sensing elements, each having a sensing structure and configured to sense a capacitive coupling between the sensing structure and a finger. The fingerprint sensing device further comprises sensing circuitry configured to provide a sensing signal indicative of the capacitive coupling between the finger and the sensing structures and timing circuitry configured to control a timing of a drive signal. The fingerprint sensing device is controllable to operate in a noise-detection mode and in a fingerprint mode. When in the noise-detection mode, the fingerprint sensing device is configured to control the timing circuitry such that a drive signal is provided. The fingerprint sensing device repeatedly senses a capacitive coupling between the finger and at least one sensing structure and provides a time-dependent sensing signal by means of said sensing circuitry.

公开(公告)号：US09842242B1

公开(公告)日：2017-12-12

申请号：US15622236

申请日：2017-06-14

Applicant: Fingerprint Cards AB

Inventor： Andreas Larsson ,  David Carling ,  Fredrik Ramberg ,  Hans Thörnblom

IPC: G06K9/00

CPC classification number: G06K9/0002 ,  G06K9/00067

Abstract: The present invention relates to a method for determining a finger movement event on a fingerprint sensor. The method comprises to acquire signals indicative of the portion of finger detecting structures that may be touched by a finger. Based on the ratio between the signals and a total signal level, the position of the finger on the fingerprint sensing device can be determined at two different time instances. Based on the positions which may be the same, a finger movement event may be determined. The invention also relates to a corresponding fingerprint sensing device.

公开(公告)号：US09600707B1

公开(公告)日：2017-03-21

申请号：US15196617

申请日：2016-06-29

Applicant: Fingerprint Cards AB

Inventor： Fredrik Ramberg ,  Hans Thörnblom ,  David Carling ,  Frank Robert Riedijk

IPC: G06F3/045 ,  G06K9/00

CPC classification number: G06K9/0002 ,  G06F3/045 ,  G06K9/00053

Abstract: There is provided a capacitive fingerprint sensing device comprising a plurality of sensing elements, sensing circuitry for providing an analog sensing signal, drive signal circuitry providing a drive signal comprising a drive pulse having a maximum level and a minimum level, providing a change in potential difference between the finger and the sensing structure, analog sampling circuitry comprising at least three analog sample and hold circuits arranged to sample the sensing signal, and a sampling control unit for individually controlling the sample and hold circuits to capture a sample at a specified time, wherein the samples comprises one sample captured when the drive signal is at a first voltage level V1 and one sample captured when the drive signal is at a second voltage level V2, different from V1; and an analog-to-digital converter, ADC, configured to convert a combination of the samples into a digital signal, wherein the three samples are captured times such that a noise component is suppressed from the sensing signal when the combination is formed.

公开(公告)号：US09600706B2

公开(公告)日：2017-03-21

申请号：US15188473

申请日：2016-06-21

Applicant: Fingerprint Cards AB

Inventor： Morten Hansen ,  Fredrik Ramberg ,  Hans Thörnblom

IPC: G06K9/00

CPC classification number: G06K9/0002 ,  G06K9/00067

Abstract: An apparatus and a computer-implemented method of acquiring a fingerprint image from a fingerprint sensor with an array of sensor elements spanning a sensing area, comprising: monitoring groups of sensor elements located at group-wise spaced apart positions in the array of sensor elements, to determine a touch event occurring on the array of sensor elements; from the array of sensor elements, acquiring, at respective points in time, fingerprint sub-images which are confined in size to a subarea of the sensing area; as the fingerprint sub-images are acquired, computing values of a statistical indicator for the fingerprint sub-images; and acquiring a full fingerprint image when a predefined criterion indicates that the values of the statistical indicator has reached or is about to reach a stable state.