Patent ID: 7355392

Claim:
A proximity sensor comprising: a multilayer printed wiring board proximity sensor including: a core formed of a permeable material, a plurality of dielectric layers in a stacked configuration, and a plurality of conductive paths extending through the stacked layers in an operatively connected configuration to form at least one coil disposed about at least a portion of the core, wherein the coils are electrically drivable to generate a magnetic field such that the inductance of the coils changes when an object is moved in relation to the magnetic field, and such that a proximity of the object is detectable based upon a change in the inductance of the coils, wherein the plurality of layers of the multilayer printed wiring board comprise: at least one core layer, each core layer comprising a core pattern formed of a permeable material, the core patterns of the core layers together comprising the core of the proximity sensor; a plurality of coil layers, each coil layer comprising a conductive path in the form of at least one coil trace formed of a conducting material formed on at least one surface of the coil layer; and a plurality of through-conductors extending through at least a portion of the core layers and the coil layers and connected to the coil traces to thereby form the coils, and wherein the core pattern of each core layer is formed of a lamination of the permeable material.