US Patent 9829614 Optical sensor using collimator

Systems and methods for optical imaging are disclosed. The optical fingerprint sensor includes an image sensor array; a collimator filter layer disposed above the image sensor array, the collimator filter layer having an array of apertures; and an illumination layer disposed above the collimator filter layer. The collimator filter layer filters reflected light such that only certain of the reflected light beams reach optical sensing elements in the image sensor array. Employing the collimator filter layer prevents blurring while allowing for a lower-profile image sensor.