FINGER BIOMETRIC SENSING DEVICE INCLUDING DRIVE SIGNAL NULLING CIRCUITRY AND RELATED METHODS
    1.
    发明申请
    FINGER BIOMETRIC SENSING DEVICE INCLUDING DRIVE SIGNAL NULLING CIRCUITRY AND RELATED METHODS 有权
    包括驱动信号的手指生物量感测装置空闲电路及相关方法

    公开(公告)号:US20130294662A1

    公开(公告)日:2013-11-07

    申请号:US13886554

    申请日:2013-05-03

    Applicant: APPLE INC.

    Abstract: A finger biometric sensing device may include drive circuitry capable of generating a drive signal and an array of finger biometric sensing pixel electrodes cooperating with the drive circuitry and capable of generating a detected signal based upon placement of a finger adjacent the array of finger biometric sensing pixel electrodes. The detected signal may include a relatively large drive signal component and a relatively small sense signal component superimposed thereon. The finger biometric sensing device may also include a gain stage coupled to the array of finger biometric sensing pixel electrodes, and drive signal nulling circuitry coupled to the gain stage capable of reducing the relatively large drive signal component from the detected signal.

    Abstract translation: 手指生物特征感测装置可以包括能够产生驱动信号的驱动电路和与驱动电路配合的手指生物测定感测像素电极的阵列,并且能够基于手指生物体感测像素阵列的放置而产生检测信号 电极。 检测到的信号可以包括相对较大的驱动信号分量和叠加在其上的相对小的感测信号分量。 手指生物特征感测装置还可以包括耦合到手指生物测量感测像素电极阵列的增益级,以及耦合到增益级的驱动信号归零电路,其能够从检测到的信号中减少较大的驱动信号分量。

    Fixed pattern noise compensation techniques for capacitive fingerprint sensors

    公开(公告)号:US09939400B1

    公开(公告)日:2018-04-10

    申请号:US14481534

    申请日:2014-09-09

    Applicant: Apple Inc.

    CPC classification number: G01N27/221 G06K9/0002

    Abstract: A capacitive fingerprint sensor includes an array of capacitive sensing elements, readout circuitry electrically coupled to the array of capacitive sensing elements, a block first digital to analog converter (DAC), at least one second DAC, and at least one summing junction electrically coupled to the readout circuitry, the first DAC, and the at least one second DAC. The readout circuitry is adapted to read out pixel voltages from a group of each block of capacitive sensing elements. The first DAC is adapted to provide a block baseline voltage for each block of capacitive sensing elements. The second DAC is adapted to provide a pixel baseline voltage difference for one capacitive sensing element of each group of each block. The summing junction is adapted to subtract the received block baseline voltage and the received pixel baseline voltage difference from the corresponding pixel voltage of each row of each block.

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