Display device with diffusive display and see-through lens assembly

Abstract

A display device includes a projector and a display that has a first surface and a second surface. The projector is configured to project image light toward the display. The display is configured to output diffused image light from the first surface and to transmit ambient light from the second surface to the first surface. The display device also includes an optical assembly that has a substrate with substantially uniform thickness. The optical assembly is configured to receive the diffused image light and transmit a portion of the diffused image light output from the first surface of the display at a first optical power. The optical assembly is also configured to receive the ambient light and transmit a portion of the ambient light through the optical assembly at a second optical power that is less than the first optical power.

What is claimed is: 
     
         1 . An optical assembly, comprising:
 a beam splitter having a first curved profile; and   a reflector having a second curved profile separate from the first curved profile, wherein the optical assembly is configured to:
 receive first light at the beam splitter and provide the first light to the reflector, and reflect the first light at the reflector and subsequently at the beam splitter before outputting the first light from the reflector, whereby the first light is transmitted through the optical assembly at a first optical power; and 
 transmit second light through the optical assembly without reflection at the reflector, wherein the second light is transmitted through the optical assembly at a second optical power that is different from the first optical power. 
   
     
     
         2 . The optical assembly of  claim 1 , wherein:
 the second optical power is less than the first optical power.   
     
     
         3 . The optical assembly of  claim 1 , further comprising:
 a display element configured to receive image light, diffuse the image light by scattering the image light, and output the diffused image light.   
     
     
         4 . The optical assembly of  claim 3 , wherein:
 the display element is further configured to receive ambient light and transmit the ambient light through the display element.   
     
     
         5 . The optical assembly of  claim 1 , further comprising:
 a display element with a first surface and a second surface opposite to the first surface.   
     
     
         6 . The optical assembly of  claim 5 , wherein the display element further comprises:
 a diffusive surface located between the first surface and the second surface, wherein the diffusive surface configured to receive image light, diffuse the image light by scattering the image light, and output the diffused image light;   a first display element portion, between the first surface and the diffusive surface, having a first refractive index; and   a second display portion, between the diffusive surface and the second surface, having a second refractive index equal to the first refractive index.   
     
     
         7 . The optical assembly of  claim 5 , wherein the display element is disposed at an image plane of the optical assembly. 
     
     
         8 . The optical assembly of  claim 7 , further comprising:
 one or more projectors disposed at an off-axis position relative to an optical axis of the display element.   
     
     
         9 . The optical assembly of  claim 5 , wherein the display element includes a plurality of nanoparticles between the first surface and the second surface. 
     
     
         10 . The optical assembly of  claim 9 , further comprising:
 a first projector configured to emit first image light having a first wavelength;   the plurality of nanoparticles includes nanoparticles having a first size; and   the nanoparticles having the first size are configured to scatter the first image light that is incident upon the first surface such that diffused first image light is output from the first surface of the display element.   
     
     
         11 . The optical assembly of  claim 10 , further comprising:
 a second projector, distinct from the first projector, that is configured to output second image light having a second wavelength that is distinct from the first wavelength;   the plurality of nanoparticles includes nanoparticles having a second size;   the nanoparticles having the second size are configured to scatter the second image light incident upon the first surface of the display element such that diffused second image light is output from the first surface of the display element;   the nanoparticles having the second size forgo scattering the first image light; and   the nanoparticles having the first size forgo scattering the second image light.   
     
     
         12 . The optical assembly of  claim 11 , wherein:
 the first image light and the second image light are visible light; and   the nanoparticles forgo scattering infrared light.   
     
     
         13 . A method, comprising:
 transmitting, with a first optical power, first light through an optical assembly that includes a beam splitter having a first curved profile and a reflector having a second curved profile separate from the first curved profile, by:
 receiving the first light at the beam splitter; 
 providing the first light to the reflector; 
 reflecting the first light at the reflector and subsequently reflecting the first light at the beam splitter; and 
 outputting the first light from the reflector; and 
   transmitting, with a second optical power that is different from the first optical power, second light through the optical assembly without reflection at the reflector.   
     
     
         14 . The method of  claim 13 , wherein:
 the second optical power is less than the first optical power.   
     
     
         15 . The method of  claim 13 , further comprising:
 with a display element with a first surface and a second surface opposite to the first surface, receiving image light at the first surface, diffusing the image light by scattering the image light, and outputting the diffused image light from the first surface.   
     
     
         16 . The method of  claim 15 , further comprising:
 with the display element, receiving ambient light at the second surface and transmitting the ambient light through the display element.   
     
     
         17 . The method of  claim 15 , wherein the display element includes a plurality of nanoparticles between the first surface and the second surface. 
     
     
         18 . The method of  claim 17 , further comprising:
 receiving, at the first surface of the display element, first image light having a first wavelength, wherein the plurality of nanoparticles includes nanoparticles having a first size; and   scattering, with the nanoparticles having the first size, the first image light that is incident upon the first surface such that diffused first image light is output from the first surface of the display element.   
     
     
         19 . The method of  claim 18 , further comprising:
 receiving, at the first surface of the display element, second image light having a second wavelength that is distinct from the first wavelength, wherein the plurality of nanoparticles also includes nanoparticles having a second size distinct from the first size; and   scattering, with the nanoparticles having the second size, the second image light that is incident upon the first surface such that diffused second image light is output from the first surface of the display element.   
     
     
         20 . The method of  claim 19 , including:
 forgoing scattering the first image light with the nanoparticles having the second size; and   forgoing scattering the second image light with the nanoparticles having the first size.