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(51) Int. Cl.(57) ABSTRACT G06F 3/04(2006.01) A touch panel is described which uses at least one infrared (52) US Cl....... 345/173; 34.5/175; 34.5/211; 178/18.09 Source and an array of infrared sensors to detect objects which (58) Field of Classification Search.......... 345/156-158, are in contact with, or close to, the touchable surface of the

345/173, 175, 176; 715/702, 740; 178/1801-19.04; panel. The panel may be operated in both reflective and

434/322-364; 315/149-150 shadow modes, in arbirary per-pixel combinations which See application file for complete search history. change over time. For example, if the level of ambient infra red is detected and if that level exceeds a threshold, shadow