Method and Apparatus for Providing a Polarization Selective Holographic Waveguide Device

Abstract

A waveguide apparatus, comprises: disposed in at least one layer: an input coupler; a first fold grating; a second fold grating; an output coupler; and a source of light optically coupled to the waveguide providing at least first and second polarizations of the light and at least one wavelength. The input coupler is configured to cause the first polarization light to travel along a first total internal reflection (TIR) path and the second polarization light to travel along a second TIR path.

What is claimed is: 
     
         1 . A waveguide apparatus, comprising: disposed in at least one layer:
 an input coupler;   a first fold grating;   a second fold grating;   an output coupler; and   a source of light optically coupled to said waveguide providing at least first and second polarizations of said light and at least one wavelength,   wherein said input coupler is configured to cause said first polarization light to travel along a first total internal reflection (TIR) path and said second polarization light to travel along a second TIR path.   
     
     
         2 . The apparatus of  claim 1  wherein said first fold grating is configured to cause said first polarization light in said first TIR path to travel along a third TIR paths to said output coupler, wherein said output coupler directs said third TIR path out of said waveguide. 
     
     
         3 . The apparatus of  claim 1  wherein said input coupler comprises first and second gratings for coupling said first and second polarization light or color into said first and second TIR paths, wherein said first and second gratings are configured as a stack or multiplexed in a single layer. 
     
     
         4 . The apparatus of  claim 1  wherein said output coupler comprises third and fourth gratings coupling said third and fourth paths out of said waveguide, wherein said first and second gratings are configured as a stack or multiplexed in a single layer. 
     
     
         5 . The apparatus of  claim 1  wherein said fold grating is configured to provide pupil expansion in a first direction, wherein said output grating is configured to provide pupil expansion in a second direction different than said first direction. 
     
     
         6 . The apparatus of  claim 1  wherein at least one of said input coupler, said fold grating or said output grating is a rolled k-vector grating. 
     
     
         7 . The apparatus of  claim 1  wherein said light undergoes a dual interaction within at least one of said fold gratings. 
     
     
         8 . The apparatus of  claim 1 , wherein said source, a microdisplay for displaying image pixels and collimation optics, and wherein said IIN projects the image displayed on said microdisplay panel such that each image pixel is converted into a unique angular direction within said first waveguide. 
     
     
         9 . The apparatus of  claim 1 , wherein said waveguide provides one of a HMD, a HUD, an eye-slaved display, a dynamic focus display or a light field display. 
     
     
         10 . The apparatus of  claim 1 , wherein at least one of said input coupler, fold grating and output grating multiplexes at least one of color or angle. 
     
     
         11 . The apparatus of  claim 1  comprising at least one grating with spatially varying pitch. 
     
     
         12 . The apparatus of  claim 1  wherein said at least one grating layer comprises a first grating layer operating at a first wavelength and a second grating layer operating at a second wavelength. 
     
     
         13 . The apparatus of  claim 1  configured to operate in the infrared. 
     
     
         14 . The apparatus of  claim 1  wherein said output coupler couples light from said waveguide onto a detector. 
     
     
         15 . The apparatus of  claim 1 , wherein at least one of said input coupler, said fold grating, and said output grating is one of a switchable Bragg grating recorded in a holographic photopolymer a HPDLC material or a uniform modulation holographic liquid crystal polymer material or a surface relief grating. 
     
     
         16 . The apparatus of  claim 1  wherein said first and second polarizations are orthogonal. 
     
     
         17 . A method of propagating light of more than one polarization component comprising the steps of:
 a) providing a waveguide containing an input grating comprising crossed first and second gratings.   b) coupling a source of light to said waveguide.   c) said first grating diffracting a first polarization state of light into a first waveguide path.   d) said second grating diffracting a second polarization state of light into a second waveguide path.   
     
     
         18 . (canceled) 
     
     
         19 . (canceled) 
     
     
         20 . (canceled)