Patent ID: 7573465

Claim:
An optical touch panel comprising: a support; an optical light guide illumination assembly arranged along and above at least most of a periphery of said support to define a detection region, said assembly including: at least one optical light guide, said at least one optical light guide having at least one light scattering discontinuity at at least one location therealong, said at least one optical light guide having optical power at at least one light transmissive region having a focus located in proximity to said discontinuity, said at least one optical light guide extending along at least most of a periphery of said detection region; and a light source arranged for directing light along said at least one optical light guide, said optical power of said at least one optical light guide and said at least one light scattering discontinuity being operative to direct light, received from said light source along said at least one optical light guide and scattered by said scattering discontinuity, generally in a plane parallel to said support such that every location in said plane receives light from generally every location along said at least one optical light guide; at least one light detector, arranged to detect changes in the light received from said optical light guide illumination assembly produced by the presence of an object in said detection region; and detection circuitry receiving at least one output from said at least one light detector and providing an output indication of the two dimensional location of said object present in said detection region.