Patent ID: 8228151

Claim:
An electromagnetic energy transducer configured to convert mechanical energy into electrical energy, comprising: two magnetic elements including a permanent magnetic element and a soft-magnetic element; and an electrical coil, wherein said permanent magnetic element and said soft-magnetic element are arranged to form a magnetic circuit, and one of the two magnetic elements is movable in relation to the other of the two magnetic elements, wherein said electrical coil surrounds a part of said soft magnetic element, wherein the movable magnetic element is held in a first position by a magnetic force of the magnetic circuit and moved into a second position by applying an external mechanical force exceeding the magnetic force, wherein at the first position the magnetic flux within the soft magnetic element is different than the flux at the second position, wherein a first and a second limit position are formed for the movement of the movable magnetic element, wherein said first limit position is defined by a first set of stop points, and said second limit position is defined by a second set of stop points, wherein the permanent magnetic element is formed as a planar integral unit comprising: a first layer having a first polarity, a second layer having a polarity opposite from that of the first polarity, a first set of protrusions corresponding to the first set of stop points, and a second set of protrusions corresponding to the second set of stop points; wherein each set of protrusions includes at least on protrusion corresponding to the first layer and at least one protrusion corresponding to the second layer.