An electronic device capable of detecting a fingerprint by optical sensing, comprising: a device screen that provides touch sensing operations and includes a display panel structure having light emitting display pixels, each pixel operable to emit light for forming a portion of a display image; a top transparent layer formed over the device screen as an interface for being touched by a user for the touch sensing operations and for transmitting the light from the display structure to display images to a user; and an optical sensor module located below the display panel structure to receive light that is emitted by at least a portion of the light emitting display pixels of the display structure and is returned from the top transparent layer to detect a fingerprint; wherein the display panel structure includes openings or holes between the light emitting display pixels of the display panel structure to allow the returned light to pass through the display panel structure to reach the optical sensor module, and the optical sensor module includes an optical sensor array that receives the returned light and an array of optical collimators located in a path of the returned light to the optical sensor array, the array of optical collimators are used to collect the returned light from the display panel structure and to separate light from different locations in the top transparent layer while directing the collected returned light to the optical sensor array; each optical collimator in the array of optical collimators is structured to transmit light in directions along or close an axis of the optical collimator while blocking light in other directions and to have a sufficiently small transmission numerical aperture to achieve a high spatial resolution by the array of optical collimators, wherein the axis of each optical collimator is perpendicular to the device screen surface. a device screen that provides touch sensing operations and includes a display panel structure having light emitting display pixels, each pixel operable to emit light for forming a portion of a display image; a top transparent layer formed over the device screen as an interface for being touched by a user for the touch sensing operations and for transmitting the light from the display structure to display images to a user; and an optical sensor module located below the display panel structure to receive light that is emitted by at least a portion of the light emitting display pixels of the display structure and is returned from the top transparent layer to detect a fingerprint; wherein the display panel structure includes openings or holes between the light emitting display pixels of the display panel structure to allow the returned light to pass through the display panel structure to reach the optical sensor module, and the optical sensor module includes an optical sensor array that receives the returned light and an array of optical collimators located in a path of the returned light to the optical sensor array, the array of optical collimators are used to collect the returned light from the display panel structure and to separate light from different locations in the top transparent layer while directing the collected returned light to the optical sensor array; each optical collimator in the array of optical collimators is structured to transmit light in directions along or close an axis of the optical collimator while blocking light in other directions and to have a sufficiently small transmission numerical aperture to achieve a high spatial resolution by the array of optical collimators, wherein the axis of each optical collimator is perpendicular to the device screen surface.