Patent ID: 7113175

Claim:
In a touch sensing system for identifying at least one active touch stimulating device, an apparatus for powering the active touch stimulating device, comprising: a touch sensing area in which said at least one active touch stimulating device operates; a transducer operatively associated with said touch sensing area for transmitting a power signal to said at least one active touch stimulating devices; a conductive layer disposed within said touch sensing area, said transducer including at least one power signal transmitter coupled to said conductive layer to generate an EM field in said conductive layer; each of said active touch stimulating devices including means for receiving said power signal and converting said power signal to electrical operating power for said active touch stimulating device; wherein said transducer includes at least one power signal transmitter coupled to peripheral portions of said conductive layer and controlled to establish an AC voltage gradient across said conductive layer; said at least one touch stimulating device including a pair of contact points adapted to electrically engage said conductive layer, said pair of contact points being movable on said conductive layer and spaced apart to acquire a voltage differential from said voltage gradient in said conductive layer.