Ergonomic head mounted display device and optical system

Abstract

This invention concerns an ergonomic optical see-through head mounted display device with an eyeglass appearance. The see-through head-mounted display device consists of a transparent, freeform waveguide prism for viewing a displayed virtual image, a see-through compensation lens for enabling proper viewing of a real-world scene when combined together with the prism, and a miniature image display unit for supplying display content. The freeform waveguide prism, containing multiple freeform refractive, and reflective surfaces, guides light originated from the miniature display unit toward a user's pupil and enables a user to view a magnified image of the displayed content. A see-through compensation lens, containing multiple freeform refractive surfaces, enables proper viewing of the surrounding environment, through the combined waveguide and lens. The waveguide prism and the see-through compensation lens are properly designed to ergonomically fit human heads enabling a wraparound design of a lightweight, compact, and see-through display system.

1 - 27 . (canceled) 
     
     
         28 . A compensation lens, to be used for viewing an external world in series with a waveguide prism, which corrects for optical distortion caused by viewing the world through the waveguide prism; where the compensation lens comprises:
 i. a refractive outer surface, disposed towards an external scene, that allows light from the external scene to enter the compensation lens,   ii. a refractive inner surface, disposed towards an outer surface of the waveguide prism, which allows light to exit the compensation lens and enter into the waveguide prism, where the refractive inner and outer surfaces of the compensation lens are mutually configured to compensate for the effect of ray shift and distortion caused by the waveguide prism;   wherein a shape of the refractive inner surface, is substantially a shape of the outer surface of the waveguide prism,   whereupon light from the external scene is refracted through the refractive outer surface and the refractive inner surface of compensation lens, before reaching the waveguide.   
     
     
         29 - 36 . (canceled) 
     
     
         37 . The compensation lens of  claim 28 , wherein a refractive medium having an index (n) greater than 1 fills a space between the refractive inner surface and the refractive outer surface. 
     
     
         38 . The compensation lens of claim  1 , wherein the compensation lens is fixed to the waveguide prism. 
     
     
         39 . The compensation lens of  claim 38 , further comprising an air gap between the compensation lens and the waveguide prism. 
     
     
         40 . The compensation lens of  claim 39 , wherein the air gap is less than 6 mm wide at any point. 
     
     
         41 . The compensation lens of  claim 39 , wherein the compensation lens is fixed to the waveguide prism with glue. 
     
     
         42 . The compensation lens of  claim 40 , wherein the glue is an index matching glue. 
     
     
         43 . The compensation lens of  claim 28 , wherein the refractive inner surface and the refractive outer surface enable a wide see-through field of view, the wide see-through field of view comprising up to 90 degrees on the temple side and up to 60 degrees on the nasal side in the horizontal direction. 
     
     
         44 . The compensation lens of  claim 43 , wherein the wide field of view comprises up to 60 degrees superiorly and up to 60 degree inferiorly in the vertical direction. 
     
     
         45 . The compensation lens of  claim 28 , wherein a shape of the refractive outer surface is substantially the same as the refractive inner surface.