An optical fingerprint sensor, includes: an image sensor array; a collimator layer disposed above the image sensor array, the collimator array having an array of first apertures; a light guiding layer disposed on the collimator layer; a light source emitting light into the light guiding layer; and a sensing area disposed above the light guiding layer. The light guiding layer allows a portion of the light from the light source to enter to the sensing area while directing the remaining portion of the light forward.