Wearable data display

Abstract

A transparent wearable data display having a source of collimated light a deflector for deflecting the collimated light into a scanned beam, and a first array including one column and integer N rows of switchable grating elements sandwiched between first and second parallel transparent substrates. The substrates together functioning as a first light guide, and a second array including M columns and N rows of switchable grating elements sandwiched between third and fourth parallel transparent substrates which together function as a second lightguide. Transparent electrodes are applied to opposing substrates. A first coupling for directing the scanned beam into a first TIR light path of the first lightguide along the first array column; and a second coupling for directing the first TIR light into a second TIR path of the second lightguide along a row of elements of the second array.

1 . A transparent wearable data display comprising:
 a source of light;   a means for collimating said light;   a means for deflecting said collimated light into a scanned beam;   a first array comprising one column containing M switchable grating elements sandwiched between first and second parallel transparent substrates, said substrates together functioning as a first light guide;   a second array comprising N columns and M rows of switchable grating elements sandwiched between third and fourth parallel transparent substrates, said substrates together functioning as a second light guide;   transparent electrodes applied to said first and second and said third and fourth substrates;   a first coupling means for directing said scanned beam into a first TIR light path between the outer surfaces of said first lightguide along said first array column; and   a second coupling means linking each element of said first array to the first element of a row of elements of said second array,   said switchable grating elements each having a diffracting state and a non diffracting state,   each element of said first array when in its diffracting state directing light via said second coupling means into a second TIR path along a row of said second array,   each element of said second array in said diffracting state deflecting light through said fourth substrate.   
     
     
         2 . The wearable data display of  claim 1  wherein at least one of said electrodes of said first array is patterned into 1×N independently switchable elements each said element overlapping one of said first array grating elements, wherein at least one of said electrodes of said second array is patterned into M×N independently switchable elements each said element overlapping one of said second array grating elements. 
     
     
         3 . The wearable data display of  claim 1  wherein said switchable grating elements each have a diffracting state when no electric field is applied across said electrodes and a non diffracting state when a field is applied across said electrodes. 
     
     
         4 . The wearable data display of  claim 1  wherein each element of said first array is disposed adjacent a first element of a row of said second array. 
     
     
         5 . The wearable data display of  claim 1  wherein each said grating element of said second array encodes image information. 
     
     
         6 . The wearable display of  claim 1  wherein said fourth substrate faces a viewer of the display. 
     
     
         7 . The wearable data display of  claim 1  wherein at any point in time said element of said second array in said diffracting state forms an image of the information encoded within said grating element at a predefined viewing range and an angular bearing defined by the instantaneous deflection angles of said scanned beam. 
     
     
         8 . The wearable data display of  claim 1  wherein said substrates of said first array are parallel to said substrates of said second array. 
     
     
         9 . The wearable data display of  claim 1  wherein said substrates of said first array are orthogonal to said substrates of said second array. 
     
     
         10 . The wearable data display of  claim 1  wherein said first coupling means is a grating device. 
     
     
         11 . The wearable data display of  claim 1  wherein said second coupling means is a grating device abutting each of said first and second arrays. 
     
     
         12 . The wearable data display of  claim 1  wherein each switchable grating element of said second array is divided into independently switchable columns aligned orthogonally to the direction of said output array TIR path. 
     
     
         13 . The wearable data display of  claim 1  wherein said switchable grating is a Switchable Bragg Grating. 
     
     
         14 . The wearable data display of  claim 1  wherein said scanned beam is characterised by angular deflections in two orthogonal directions. 
     
     
         15 . The wearable data display of  claim 1  wherein the intensity of said scanned beam is modulated by varying the refractive index modulation of at least one of the switchable grating elements traversed by the beam. 
     
     
         16 . The wearable data display of  claim 1  wherein said light comprises first, second and third wavelength light. 
     
     
         17 . The wearable data display of  claim 1  wherein said light comprises first second and third wavelength light and each switchable grating element is a multiplexed SBG comprising a first grating for diffracting said first wavelength light and a second grating for diffracting said second and third wavelength light. 
     
     
         18 . The wearable data display of  claim 1  wherein said light comprises first second and third wavelength light and each switchable grating element is a multiplexed SBG comprising a first grating for diffracting said first wavelength light, a second grating for diffracting said second wavelength light and a third grating for diffracting said third wavelength light. 
     
     
         19 . The wearable data display of  claim 1  wherein each said switchable grating is a surface relief grating backfilled with an electrically variable refractive index medium. 
     
     
         20 . The wearable data display of  claim 1  wherein each switchable grating element in at least one of said first array and said second array is divided into independently switchable columns aligned orthogonally to said TIR paths, wherein the refractive index modulation of each element in said switchable column is dynamically controlled such that a predetermined amount of light is diffracted by said switchable column through said fourth substrate. 
     
     
         21 . The wearable data display of  claim 1  wherein said data display is one of a pair of left and right eyepieces. 
     
     
         22 . The wearable data display of  claim 1  wherein said means for deflecting said collimated light is an electro optical device. 
     
     
         23 . The wearable data display of  claim 1  wherein said means for deflecting said collimated light comprises:
 a first transparent optical substrate with an input surface and an output surface; 
 a second transparent optical substrate with an input surface and an output surface; 
 transparent electrodes applied to said output surface of said first substrate and said input surface of said second substrate; 
 an electrically variable refractive index layer having a planar surface and a second surface shaped to provide an array of prisms; and 
 a fixed refractive index layer having a planar surface and a second surface shaped to provide an array of prismatic cavities, said prisms and said prismatic cavities having 
 identical and opposing geometries, each said prism abutting one of said prismatic cavities, 
 wherein said planar surface of said variable refractive index layer abuts said output surface of said first substrate and said planar surface of said fixed refractive index layer abuts said input surface of said second substrate, wherein said transparent electrodes are electrically couple to a variable voltage generating means, 
 wherein at least one of said transparent electrodes is patterned into independently switchable electrode elements having substantially the same cross sectional area as said prisms such that said variable refractive index prisms may be selectively switched in discrete steps from a fully diffracting to a non diffracting state by an electric field applied across said transparent electrodes.