US Patent 7781722 Optical touch screen assembly

An optical touch panel including a support defining a detection region, an optical illumination assembly including at least two edge emitting optical light guides extending along adjacent portions of the detection region and having ends adjacent to one another and at least one mechanical coupling and optical coupling assembly, at least one sensor assembly, operative to detect changes in the light received from the optical illumination assembly produced by the presence of an object in the detection region and detection circuitry receiving at least one output from the at least one sensor assembly and providing an output indication of the two dimensional location of object impingement in the detection region.