Patent ID: 8531431

Claim:
A touch sensor capable of determining at least one position of at least one conducting object with respect to a display device of the touch sensor, comprising: in the display device a first substrate on which at least a first display electrode is disposed and a second substrate on which at least a second display electrode is disposed, for the display of a shape on the display device; an interface coupled to at least one of the first display electrode or the second display electrode for receiving display data to the display device; a measuring circuit coupled to the at least one display electrode; a switching circuit for: connecting the interface to the at least one display electrode when the switching means is in a first state of operation; disconnecting the interface from the at least one display electrode; and connecting the measuring circuit to the at least one display electrode when the switching circuit is in a second state of operation, wherein the switching circuit is adapted to preserve the voltage value between the first display electrode on the first substrate and the second display electrode on the second substrate when the switching circuit is in the second state of operation, wherein the measuring circuit, when the switching circuit is in the second state of operation, is adapted to perform at least one measurement of the capacitive load of the at least one display electrode, and wherein the measurement is performed by, at a time instant: charging at least one capacitive load of the at least one display electrode by a predefined signal, wherein the charging results in at least one charging curve; determining the size of the at least one capacitive load of the at least one display electrode by measuring at least one rise time of the at least one charging curve; and calculating at least one position of the at least one conducting object, with respect to the display device, based on the determined size of the at least one capacitive load.