Multi-microlens fingerprint sensor with photodiodes in groups; each photodiode of the photodiode groups having a field of view through a microlens, pinholes of an upper black mask layer, and pinholes of a metal layer having pinhole rings with pinholes of an outer ring larger than those of an inner ring

Abstract

An image sensor for imaging fingerprints has multiple photodiode groups each having a field of view determined by pinholes of upper and lower mask layers and a metal layer, each field of view being through a microlens. Many photodiode groups have fields of view outwardly splayed from a group having a center-direct field of view. A diameter of pinholes of the metal layer distant from the group having a center-direct field of view have larger diameter than a pinhole of the photodiode group having a center-direct field of view. A method of matching illumination of a group of photodiodes with center-direct field of view to illumination of photodiode groups having outwardly splayed fields of view includes sizing a pinhole in the metal layer of photodiode groups with outwardly splayed fields of view larger than a pinhole associated with of photodiode groups having a center-direct field of view.