This invention relates to devices for coupling light between an optical
waveguide and an optical element in a manner that is substantially
independent of temperature, using reflective optics. Certain embodiments
of the invention concern improved designs for the transmit and receive
optics of a waveguide-based optical touch screen sensor, incorporating
reflective optics. The improved designs have substantially temperature
independent operation and reduced optical losses. In one preferred
embodiment the improved design incorporates a parabolic or
quasi-parabolic reflector. In another preferred embodiment the improved
design incorporates an elliptical or quasi-elliptical reflector. The
transmit and receive elements and associated waveguides preferably
comprise photo-patternable polymers.