Patent attributes
A compact optical system with improved contrast for a head-worn computer includes a light source including a lens with positive optical power positioned within the head-worn computer and adapted to project converging illuminating light towards a partially reflective partially transmissive surface wherein the illuminating light forms a spot with an area smaller than the light source on the partially reflective partially transmissive surface prior to being reflected as diverging illuminating light that passes through a field lens and towards a reflective display. The illuminating light reflects off a surface of the reflective display, forming diverging image light which is transmitted through the field lens and then through the partially reflective partially transmissive surface to a lower display optical system adapted to present the image light to an eye of a user wearing the head-worn computer.