Optical touch system comprising means for projecting and detecting light beams above and inside a transmissive panel

A touch sensing apparatus, comprising:

• a panel having a touch surface and a bottom surface;
• a plurality of emitters arranged around a portion of the periphery of the touch surface to emit beams of light;
• a diffusive reflecting surface of a non-transmissive frame component arranged around a portion of the periphery of the touch surface, said diffusive reflecting surface configured to spread out the emitted beams of light across the touch surface and form overlapping detection lines;
• said diffusive reflecting surface comprising a first edge proximal to a plane of the touch surface and a second edge distal to the plane of the touch surface, and wherein the second edge is closer to a center point of the touch surface than the first edge such that the diffusive reflecting surface forms an acute angle with the touch surface,
• a plurality of light detectors arranged around a portion of the periphery of the touch surface, said plurality of light detectors configured to receive light from the plurality of emitters, wherein each of the plurality of light detector is arranged to receive light from more than one of the plurality of emitters;
• and
• a processing element configured to determine, based on output signals generated from the plurality of light detectors, a position of an object on the touch surface.