Patent ID: 9207784
Filing Date: 2015-12-08
Classification: G06F

Abstract:
1. An electromagnetic pointer, comprising: a core having a tip; an oscillation circuit including a plurality of conductive terminals and a conductive cone spring positioned between a proximal end of the core and the conductive terminals, a periphery of a base of the conductive cone spring being in electrical contact with a peripheral one of the conductive terminals, wherein when the core axially moves between an extended position and a retracted position, the center of the conductive cone spring correspondingly moves between a first position, at which it is not in electrical contact with a central one of the conductive terminals, and a second position, at which it comes in electrical contact with said central one of the conductive terminals, to thereby change a capacitance of the oscillation circuit and cause a sudden change in a frequency of the oscillation circuit; a switch; and a controller, which, in operation: