DETERMINING THE ORIENTATION OF AN OBJECT

摘要

A touch screen (10) is disclosed comprising a plurality of light emitters (Lo....L₁₅) and light detectors (S_o....S₁₁) arranged around a periphery thereof. The position, shape and size of objects (16) may be determined by switching the light emitters on one-by-one and detecting shadows (18) caused by the objects. The objects comprise at least a first part with optical properties of a first type and a second part with optical properties of a second different type. By determining the optical phenomena caused by the second part, the orientation of the objects may be determined and/or the objects may be recognized or identified.