Dual film light guide for illuminating displays

Abstract

A front light guide panel including a plurality of embedded surface features is provided. The front light panel is configured to deliver uniform illumination from an artificial light source disposed at one side of the font light panel to an array of display elements located behind the front light guide while allowing for the option of illumination from ambient lighting transmitted through the light guide panel. The surface embedded surface relief features create air pockets within the light guide panel. Light incident on the side surface of the light guide propagates though the light guide until it strikes an air/light material guide interface at one on the air pockets. The light is then turned by total internal reflection through a large angle such that it exits an output face disposed in front of the array of display elements.

1 . A light guide comprising:
 an upper portion having top and bottom surfaces, said bottom surface of said upper portion being contoured; and   a lower portion having top and bottom surfaces, said top surface of said lower portion being contoured,   wherein said upper portion is disposed over said lower portion such that said contoured bottom surface of said upper portion and said contoured top surface of said lower portion form cavities between the upper portion and the lower portion.   
   
   
       2 . The light guide of  claim 1 , wherein said upper and lower portions comprise films having a contoured surface imprinted with surface relief features. 
   
   
       3 . The light guide of  claim 2 , wherein said surface relief features comprise a plurality of elongate microprisms. 
   
   
       4 . The light guide of  claim 3 , wherein said microprisms each comprise at least two adjacent facets angled with respect to each other. 
   
   
       5 . The light guide of  claim 4 , wherein said at least two adjacent facets have different angles of inclination with respect to said film. 
   
   
       6 . The light guide of  claim 5 , wherein said angles of inclination vary over the length of the film. 
   
   
       7 . The light guide of  claim 4 , wherein the two adjacent facets comprise curved surfaces. 
   
   
       8 . The light guide of  claim 4 , wherein the microprisms comprise two sides, each side being multifaceted. 
   
   
       9 . The light guide of  claim 2 , wherein distance between surface relief features ranges from 50 to 450 microns. 
   
   
       10 . The light guide of  claim 2 , wherein distance between adjacent surface relief features varies over the length of the film. 
   
   
       11 . The light guide of  claim 10 , wherein said upper and lower portions include an edge through which light can be injected and wherein said distance between adjacent surface relief features decreases as the distance from said edge increases. 
   
   
       12 . The light guide of  claim 1 , wherein said light guide includes an edge through which light can be injected, said injected light being scattered out of said light guide at said cavities. 
   
   
       13 . The light guide of  claim 1 , wherein said cavities comprise air pockets. 
   
   
       14 . The light guide of  claim 13 , wherein said air pockets are asymmetrical. 
   
   
       15 . The light guide of  claim 1 , wherein said cavities are filled with a filler material. 
   
   
       16 . The light guide of  claim 1 , wherein said light guide includes an edge through which light can be injected, further comprising a light source positioned adjacent said edge. 
   
   
       17 . The light guide of  claim 16 , wherein light from said light source is scattered out of said bottom surface of said lower portion by said cavities surface. 
   
   
       18 . The light guide of  claim 1 , wherein said contoured bottom surface of said upper portion and said contoured top surface of said lower portion comprise a plurality of elongate grooves. 
   
   
       19 . The light guide of  claim 18 , wherein said grooves comprise inclined planar surfaces. 
   
   
       20 . The light guide of  claim 18 , wherein at least some of the grooves in the bottom surface of the upper portion have the same shape or at least some of the grooves in the top surface of the lower portion have the same shape. 
   
   
       21 . The light guide of  claim 18 , wherein the grooves are asymmetrical. 
   
   
       22 . The light guide of  claim 18 , wherein the distance between said grooves varies across the length of the film. 
   
   
       23 . The light guide of  claim 18 , wherein the distance between said grooves ranges from 50 to 450 microns. 
   
   
       24 . The light guide of  claim 1 , wherein the top surface of the upper portion is parallel to the bottom surface of the lower portion. 
   
   
       25 . The light guide of  claim 1 , wherein a first part of the top surface of the upper portion is not parallel to a first part of the bottom surface of the lower portion. 
   
   
       26 . The light guide of  claim 25 , wherein a second part of the top surface of the upper portion is parallel to a second part of the bottom surface of the lower portion. 
   
   
       27 . The light guide of  claim 1 , wherein the top surface of the upper portion is not parallel to the bottom surface of the lower portion. 
   
   
       28 . The device of  claim 1 , further comprising:
 an array of display elements;   a processor that is in electrical communication with said display elements, said processor being configured to process image data; and   a memory device in electrical communication with said processor.   
   
   
       29 . The device of  claim 28 , further comprising a driver circuit configured to send at least one signal to said display elements. 
   
   
       30 . The device of  claim 29 , further comprising a controller configured to send at least a portion of said image data to said driver circuit. 
   
   
       31 . The device of  claim 28 , further comprising an image source module configured to send said image data to said processor. 
   
   
       32 . The device of  claim 31 , wherein said image source module comprises at least one of a receiver, transceiver, and transmitter. 
   
   
       33 . The device of  claim 28 , further comprising an input device configured to receive input data and to communicate said input data to said processor. 
   
   
       34 - 92 . (canceled)