System for and method of projecting augmentation imagery in a head-mounted display

Abstract

A system for and method of projecting augmentation imagery in a head-mounted display is disclosed. A system for projecting light onto an eye includes a display to project light, a beam combiner, first and second optical systems between the display and the beam combiner along respective first and second optical paths. The first and second optical paths differ. The system also includes a switchable reflector that, in a reflective state, reflects light incident upon the reflector, and, in a non-reflective state, transmits light incident upon the reflector. The reflector is between the display and the first and second optical systems along the first and second optical paths and directs light along the first path, in the reflective state, or along the second path, in the non-reflective state, to reflect light from the beam combiner to the eye from different directions when in the different states.

What is claimed is: 
     
         1 . A system for projecting light onto an eye, the system comprising:
 a display configured to project light;   a beam combiner;   a first optical system disposed between the display and the beam combiner along a first optical path;   a second optical system disposed between the display and the beam combiner along a second optical path, wherein the second optical path is different from the first optical path; and   a switchable reflector configured to selectively switch between:
 a reflective state, in which light incident upon the switchable reflector is reflected by the switchable reflector, and 
 a non-reflective state, in which light incident upon the switchable reflector is transmitted via the switchable reflector, 
   the switchable reflector disposed between the display and the first and second optical systems along the first and second optical paths to direct the light along the first optical path to the beam combiner when in the reflective state, such that the light is reflected off the beam combiner and projected upon an eye from a first direction, and to direct the light along the second optical path to the beam combiner when in the non-reflective state, such that the light is reflected off the beam combiner and projected upon the eye from a second direction different from the first direction.   
     
     
         2 . The system of  claim 1 , wherein the light is viewable by the eye in a first field of view when the light is projected upon the eye from the first direction, and the light is viewable by the eye in a second field of view when the light is projected upon the eye from the second direction. 
     
     
         3 . The system of  claim 2 , wherein the first field of view is at least 30°. 
     
     
         4 . The system of  claim 2 , wherein the first optical system is configured to project the light over the first field of view, the second optical system is configured to project the light over the second field of view, and the first field of view overlaps the second field of view by at least 10°. 
     
     
         5 . The system of  claim 1 , further comprising:
 an eye tracking system configured to determine an orientation of the eye relative to the beam combiner; and   a controller configured to switch the switchable reflector between the reflective state and the non-reflective state based at least in part on the orientation of the eye.   
     
     
         6 . The system of  claim 1 , wherein the switchable reflector has a clear aperture having a width of at least 2 mm. 
     
     
         7 . The system of  claim 1 , wherein at least one of the first optical system and the second optical system comprises a foveated optical system. 
     
     
         8 . The system of  claim 7 , wherein the foveated optical system comprises a liquid crystal wave front corrector. 
     
     
         9 . The system of  claim 1 , wherein the switchable reflector comprises a liquid crystal mirror. 
     
     
         10 . The system of  claim 1 , wherein at least one of the first optical system and the second optical system is configured to collimate the light, and wherein the beam combiner is partially reflective. 
     
     
         11 . The system of  claim 1 , wherein the display is configured to linearly polarize the light. 
     
     
         12 . The system of  claim 1 , wherein at least a portion of the beam combiner is curved to collimate light that is reflected to the eye. 
     
     
         13 . The system of  claim 1 , wherein the first optical path is longer than the second optical path. 
     
     
         14 . The system of  claim 1 , further comprising a reflector disposed between the switchable reflector and the first optical system along the first optical path. 
     
     
         15 . The system of  claim 1 , wherein the switchable reflector reflects substantially all light incident upon the switchable reflector in the reflective state. 
     
     
         16 . The system of  claim 1 , wherein the display comprises:
 a first sub-display that projects a first group of light rays having a first resolution; and   a second sub-display that projects a second group of light rays having a second resolution different than the first resolution; and   the projected light comprises the first group of light rays and the second group of light rays.   
     
     
         17 . A method of projecting an image onto an eye, the method comprising:
 projecting light defining an image, via a display, onto a switchable reflector; and   selectively switching the switchable reflector between a reflective state and a non-reflective state:
 wherein when the switchable reflector is in the reflective state, the light incident upon the switchable reflector is reflected by the switchable reflector and directed along a first optical path to a beam combiner, and the directed light reflects off the beam combiner and is projected upon an eye from a first direction; and 
 wherein when the switchable reflector is in the non-reflective state, the light incident upon the switchable reflector is transmitted via the switchable reflector and directed along a second optical path, different from the first optical path, to the beam combiner, and the directed light reflects off the beam combiner and is projected upon the eye from a second direction. 
   
     
     
         18 . The method of  claim 17 , further comprising tracking an orientation of the eye relative to the beam combiner, and wherein the selectively switching the switchable reflector is performed based at least in part on the orientation of the eye. 
     
     
         19 . The method of  claim 17 , wherein, when the switchable reflector is in the non-reflective state, the light incident upon the switchable reflector is transmitted via a clear aperture defined in the switchable reflector, the clear aperture having a width of about 2 mm to about 10 mm. 
     
     
         20 . The method of  claim 17 , wherein projecting the light defining an image onto the switchable reflector comprises projecting a foveated image. 
     
     
         21 . The method of  claim 17 , wherein the switchable reflector comprises a liquid crystal mirror. 
     
     
         22 . The method of  claim 17 , wherein the first optical path is defined in part by a first optical system configured to project the directed light over a first field of view, and the second optical path is defined in part by a second optical system configured to project the directed light over a second field of view, and the first field of view overlaps the second field of view by at least 10°. 
     
     
         23 . The method of  claim 22 , further comprising at least one of the first optical system and the second optical system collimating the light that defines the image, and wherein the beam combiner is partially reflective. 
     
     
         24 . The method of  claim 17 , wherein the display linearly polarizes the light that defines the image. 
     
     
         25 . The method of  claim 17 , further comprising the beam combiner collimating the light comprising the image that is reflected to the eye. 
     
     
         26 . The method of  claim 17 , wherein the first optical path is longer than the second optical path. 
     
     
         27 . The method of  claim 17 , further comprising reflecting light from a reflector disposed between the switchable reflector and the first optical system along the first optical path. 
     
     
         28 . The method of  claim 17 , wherein the switchable reflector reflects substantially all light incident upon the switchable reflector in the reflective state. 
     
     
         29 . The method of  claim 17 , wherein at least one of the first optical system and the second optical system comprise a liquid crystal wave front corrector. 
     
     
         30 . The method of  claim 17 , wherein projecting the light comprises:
 projecting a first group of light rays having a first resolution; and   projecting a second group of light rays having a second resolution different for the first resolution; and   the projected light comprises the first group of light rays and the second group of light rays.