Apparatus and method for a folded optical element waveguide for use with light based touch screens

Abstract

A folded optical element waveguide that allows a minimum width bezel to be used around the perimeter of a light-based touch screen display. The apparatus and method includes a touch screen and a waveguide substrate provided adjacent the touch screen. The waveguide substrate includes a plurality of waveguides and a plurality of optical elements provided adjacent the touch screen. The waveguides include an internally reflective surface to reflect light perpendicular to the surface of the touch screen. The emitting and detecting waveguides are thus folded and provided around the side edges of the display. As a result, the width of the bezel around the display can be minimized.

1 . An apparatus, comprising;
 a touch screen having a display surface;   a bezel supporting therein the touch screen, the bezel having a sidewall that is not coplanar with the display surface;   said bezel sidewall comprising an array of waveguides associated with a reflector that one of:   directs light from one of said waveguides adjacent to said display surface; or   receives light from adjacent to said display surface and directs it into a waveguide;   the array of waveguides comprising,
 a first set of waveguides arranged on the a first sidewall of the bezel; 
 a second set of waveguides arranged on the a second sidewall of the bezel; and 
 wherein the first and second sidewalls are arranged at opposite sides of the touch screen. 
   
     
     
         2 . The apparatus recited in  claim 1  wherein the reflector is integral to an associated waveguide. 
     
     
         3 . The apparatus recited in  claim 2  wherein the integral reflector comprises a mirrored surface at a bend in the associated waveguide. 
     
     
         4 . The apparatus recited in  claim 1  wherein the reflector is distinct from and located proximal to an associated waveguide. 
     
     
         5 . The apparatus recited in  claim 1  wherein,
 the first set of waveguides is associated with a light source that is projected through the first set of waveguides; 
 the second set of waveguides is associated with a light detector that detects light received by the second set of waveguides; and 
 light projected through the first set of waveguides and received by the second set of waveguides forms an interruptable light pattern proximal to the display surface of the touch screen, the pattern formed such that the location of interruptions to the light pattern can be determined. 
 
     
     
         6 . The apparatus recited in  claim 5  wherein the interruptable light pattern comprises a grid of light extending over the display surface of the touch screen. 
     
     
         7 . The apparatus recited in  claim 5  wherein the interruptable light pattern comprises a contiguous lamina of light extending over the display surface of the touch screen. 
     
     
         8 . The apparatus recited in  claim 7  wherein the contiguous lamina of light is in the range of about 1 millimeter to 4 millimeters thick. 
     
     
         9 . The apparatus recited in  claim 5  wherein,
 a third set of waveguides arranged on a third sidewall is associated with a light source that is projected through the first set of waveguides; 
 the second set of waveguides is associated with a light detector that detects light received by the second set of waveguides; and 
 light projected through the first set of waveguides and received by the second set of waveguides forms an interruptable light pattern proximal to the display surface of the touch screen, the pattern formed such that the location of interruptions to the light pattern can be determined. 
 
     
     
         10 . The apparatus recited in  claim 1  wherein an outer portion of the sidewall supports the array of waveguides. 
     
     
         11 . The apparatus recited in  claim 1  wherein the reflector comprises a light reflecting means for one of:
 directing light from one of said waveguides adjacent to said display surface; or 
 receiving light from adjacent to said display surface and directing it into one of said waveguides.