A touch panel in which two or more light sensors emit light into a
transparent panel at an angle to sustain transmission through the panel
by total internal reflection. The transmitted light is detected at an
array of light detection positions around the periphery of the panel
opposite to each light source. When an object contact the surface of the
panel, light transmitted along the pathway from a given source past the
contact point to one of the detection points is attenuated by the
frustrated total internal reflection (FTIR) effect. Each contact causes
two or more intersecting light beams having known end points to be
attenuated, enabling a connected processor to determine the position and
size of the contact area.