Patent attributes
An eyewear device has an optical element, a patterned optical filter, and a camera. The optical element receives light that includes light in a visible band and light in an infrared (IR) band. The patterned optical filter is disposed on the optical element and has a filtering portion and a plurality of non-filtering portions. The filtering portion is transmissive to light in the visible band and filtering of light in the IR band. The non-filtering portions are transmissive to light in the visible band and transmissive to light in the IR band. Some portion of the received light in the IR band passes through the non-filtering portions and illuminates a portion of an eye of a user with a pattern. The camera captures images of the portion of the eye that is illuminated with the pattern.