Dispersion compensation in volume bragg grating-based waveguide display

Abstract

A waveguide display includes a substrate transparent to visible light, a coupler configured to couple display light into the substrate as guided wave in the substrate, and a first VBG and a second VBG coupled to the substrate. The coupler includes a diffractive coupler, a refractive coupler, or a reflective coupler. The first VBG is configured to diffract, at a first region of the first VBG, the display light in the substrate to a first direction, and diffract, at two or more regions of the first VBG along the first direction, the display light from the first region to a second direction towards the second VBG. The second VBG is configured to couple the display light from each of the two or more regions of the first VBG out of the substrate at two or more regions of the second VBG along the second direction.

What is claimed is: 
     
         1 . A waveguide display comprising:
 a substrate transparent to visible light; and   a first volume Bragg grating (VBG), a second VBG, and a third VBG coupled to the substrate,   wherein the first VBG is configured to couple display light into the substrate as guided wave towards a first region of the second VBG;   wherein the second VBG is configured to:
 diffract, at the first region of the second VBG, the display light from the first VBG to a first direction; and 
 diffract, at two or more regions of the second VBG along the first direction, the display light from the first region to a second direction towards the third VBG; and 
   wherein the third VBG is configured to couple the display light from each of the two or more regions of the second VBG out of the substrate at two or more regions of the third VBG along the second direction.   
     
     
         2 . The waveguide display of  claim 1 , wherein the first VBG and the third VBG have a same grating vector in a plane perpendicular to a surface normal direction of the substrate. 
     
     
         3 . The waveguide display of  claim 1 , wherein the first VBG, the second VBG, and the third VBG are configured to diffract the display light from a same field of view range and in a same wavelength range. 
     
     
         4 . The waveguide display of  claim 1 , wherein each of the first VBG, the second VBG, and the third VBG includes a reflective VBG or a transmissive VBG. 
     
     
         5 . The waveguide display of  claim 1 , wherein:
 the third VBG includes a transmissive VBG; and   the second VBG overlaps with the third VBG in a see-through region of the waveguide display.   
     
     
         6 . The waveguide display of  claim 1 , wherein at least one of the first VBG, the second VBG, or the third VBG includes a multiplexed VBG. 
     
     
         7 . The waveguide display of  claim 6 , wherein:
 the first VBG includes a first set of VBGs;   the third VBG includes a second set of VBGs; and   each VBG in the first set of VBGs and a corresponding VBG in the second set of VBGs have a same grating vector in a plane perpendicular to a surface normal direction of the substrate and are configured to diffract the display light from a same field of view range and in a same wavelength range.   
     
     
         8 . The waveguide display of  claim 6 , wherein at least one of the first VBG, the second VBG, or the third VBG includes VBGs in two or more holographic material layers. 
     
     
         9 . The waveguide display of  claim 8 , further comprising a polarization convertor between two holographic material layers of the two or more holographic material layers. 
     
     
         10 . The waveguide display of  claim 1 , further comprising an anti-reflection layer configured to reduce reflection of ambient light into the substrate. 
     
     
         11 . The waveguide display of  claim 1 , further comprising an angular-selective transmissive layer configured to reflect, diffract, or absorb ambient light incident on the angular-selective transmissive layer with an incidence angle greater than a threshold value. 
     
     
         12 . The waveguide display of  claim 1 , wherein:
 each of the second VBG and the third VBG is characterized by a respective thickness less than 100 μm; and   the waveguide display is characterized by an angular resolution less than 2 arcminutes.   
     
     
         13 . The waveguide display of  claim 1 , wherein the first region of the second VBG and a second region of the two or more regions of the second VBG have a same grating vector in a plane perpendicular to a surface normal direction of the substrate. 
     
     
         14 . The waveguide display of  claim 1 , further comprising:
 a light source configured to generate the display light; and   projector optics configure to collimate the display light and direct the display light to the first VBG.   
     
     
         15 . A waveguide display comprising:
 a substrate transparent to visible light;   a coupler configured to couple display light into the substrate as guided wave in the substrate; and   a first volume Bragg grating (VBG) and a second VBG coupled to the substrate,   wherein the first VBG is configured to:
 diffract, at a first region of the first VBG, the display light in the substrate to a first direction; and 
 diffract, at two or more regions of the first VBG along the first direction, the display light from the first region to a second direction towards the second VBG; and 
   wherein the second VBG is configured to couple the display light from each of the two or more regions of the first VBG out of the substrate at two or more regions of the second VBG along the second direction.   
     
     
         16 . The waveguide display of  claim 15 , wherein:
 the first VBG is characterized by a thickness less than 100 μm; and   the waveguide display is characterized by an angular resolution less than 2 arcminutes.   
     
     
         17 . The waveguide display of  claim 15 , wherein:
 the second VBG includes a transmissive VBG; and   the first VBG overlaps with the second VBG in a see-through region of the waveguide display.   
     
     
         18 . The waveguide display of  claim 15 , wherein at least one of the first VBG or the second VBG includes VBGs in two or more holographic material layers. 
     
     
         19 . The waveguide display of  claim 15 , wherein the coupler includes a diffractive coupler, a refractive coupler, or a reflective coupler. 
     
     
         20 . The waveguide display of  claim 15 , wherein at least one of the first VBG or the second VBG includes a multiplexed VBG. 
     
     
         21 . The waveguide display of  claim 15 , wherein each of the first VBG and the second VBG includes a transmissive VBG or a reflective VBG. 
     
     
         22 . The waveguide display of  claim 15 , wherein the first region of the first VBG and a second region of the two or more regions of the first VBG have a same grating vector in a plane perpendicular to a surface normal direction of the substrate.