Compact optical system for head-worn computer

Abstract

An optical system for a head-worn computer includes a light source positioned within the head-worn computer and adapted to project polarized illuminating light towards a partially reflective partially transmissive surface such that the illuminating light reflects through a field lens and towards a reflective display. The illuminating light reflects off a surface of the reflective display, forming image light. The image light is then 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.

What is claimed is: 
     
         1 . An optical system for a head-worn computer, comprising:
 a light source positioned within the head-worn computer and adapted to project polarized illuminating light towards a partially reflective partially transmissive surface such that the illuminating light reflects through a field lens and towards a reflective display,   wherein the illuminating light reflects off a surface of the reflective display, forming image light, and   wherein the image light is then 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.   
     
     
         2 . The optical system of  claim 1 , wherein the partially reflective partially transmissive surface is a film that includes a flat segment. 
     
     
         3 . The optical system of  claim 1 , wherein the partially reflective partially transmissive surface is a reflective polarizer. 
     
     
         4 . The optical system of  claim 3 , wherein the reflective display is an LCOS or an FLCOS. 
     
     
         5 . The optical system of  claim 1 , wherein the field lens has less than 30 nm birefringence. 
     
     
         6 . The optical system of  claim 1 , wherein the lower display optical system also provides a see-through view of the surrounding environment. 
     
     
         7 . The optical system of  claim 1 , wherein the partially reflective partially transmissive surface is a combined polarizer including a centrally located reflective polarizer that reflects illuminating light to an active area of the reflective display, attached to a larger absorptive polarizer, that absorbs excess illuminating light.