Patent ID: 8022928

Claim:
Method of determining the position of a portable free-space data input device comprising the steps of: receiving, in an optical position detecting device, a first set of pulses from the portable free-space data input device comprising at least one pulse including data to be processed, receiving, in said optical position detecting device, a second set of pulses in the form of light pulses from the portable free-space data input device comprising at least one position indication pulse, limiting a pulse of the second set of pulses to at least one first bundle of rays of light having a certain first cross-sectional shape, projecting said at least one bundle onto a plane, where at least a first one-dimensional detector array is provided, for creating a pattern of light and dark areas in said plane, detecting, in each detector array, a part of the pattern projected on it, and determining the position of the portable free-space data input device in at least two dimensions based on junctions between light and dark areas of parts of the pattern detected by each detector array in order to allow the use of said position together with said input data, and wherein said first set of pulses comprises at least one start pulse indicating start of data to be processed and at least one end pulse indicating an end of data to be processed and further comprising the steps of activating all detector arrays when said start pulse is received and deactivating all detector arrays when said end pulse is received.