Determining the orientation of an object

A plurality of photogens (L) arranged on the outskirts0- L15And an optical power detector (S)0- S11An included touch screen display (10) is indicated. A target (16) position, a form, and a size can switch on a photogen one by one, and can determine them by detecting a shadow (18) caused by object. An object contains the 2nd portion with the optical characteristic of a type that the 2nd differs from the 1st portion with the optical characteristic of 1st at least one type. By determining an optical phenomenon caused by the 2nd portion, the direction of an object can be determined and/or can carry out recognition or the same check of the object.