摘要 |
The sensor has a sensing matrix (20) comprising sensing units for sensing objects in the form of a matrix, driving means (40, 50, 63) for receiving the signals representing the states of the sensing units, and sensing means (30) for sensing the existence position of the object on the sensing matrix (20) on the basis of the signals received by the driving means. The sensing means (30) is provided with an offsetting means (30a) for storing the values of the received signal as an offset value for every sensing unit while updating successively, a computing means (30b) for computing the difference between the offset value before updating and the newly received signal value for every respective sensing unit, and a comparing means (30c) for judging the existence of the object by comparing the difference between both of the values with a preset value. <IMAGE> |