Patent ID: 7465914

Claim:
A system for determining a position of a radiation reflecting/scattering element, the system comprising: a transmissive element or plate having a first surface part adapted to be engaged by the reflecting/scattering element and a second surface part being opposite to the first surface part, a radiating element adapted to provide radiation into the transmissive element and onto the first surface part, a detector adapted to detect radiation provided by the radiating element and that is reflected/scattered by the reflecting/scattering element when engaging the first surface part at a position thereof and outputting a signal relating to an angle of incidence of the radiation, the transmissive element being adapted to guide the reflected/scattered light via total internal reflection to the detector, the detector being at least one at least one-dimensional detector having a plurality of detecting elements each being adapted to detect radiation and to output a corresponding signal, at least one aperture, pinhole, or lens arranged between the transmissive element and the detector and adapted to modulate radiation incident on the detecting elements, and a determining element adapted to determine, on the basis of angle signal, a position of engagement of the reflecting/scattering element on the first surface part.