Compact optical sensor for fingerprint detection

Abstract

The present disclosure relates to an optical sensor for use in an image recognition device, such as a fingerprint detector. The presently disclosed optical sensor has improved light transmittance in a compact and cost-efficient structure. In particular the presently disclosed optical sensor can be placed under a display panel of an electronic device, such as a smartphone. One embodiment relates to an optical sensor system for placement under a display panel for detecting/imaging light returned from a fingerprint on top of the display panel, the optical sensor comprising a microlens structure having a front side with an array of light focusing elements and an opaque back side with an array of optically transparent apertures aligned with the focusing elements, and a sensor array of optical detectors facing the back side of the microlens structure. The optical sensor system is preferably configured such that light returned from the object can be focused by the microlens structure onto the sensor array through the transparent apertures.