Patent ID: 7501834
Filing Date: 2009-03-10
Classification: H02K,H02P

Abstract:
1. A voice coil actuator having a capacitive sensor, comprising: a magnetic housing containing at least one magnet, the magnetic housing having a wall that defines a first cavity; a magnetic core coupled to the magnetic housing and extending from an interior surface of the magnetic housing in a direction of a center axis of the wall of the magnetic housing; and a coil assembly having a wall defining a second cavity that at least partly envelops the magnetic core, disposed at least partly inside the first cavity, and adapted to move linearly with respect to the magnetic housing, wherein the coil assembly has formed thereon at least two electrically conducive areas; wherein the coil assembly forms the capacitive sensor with the magnetic core, the capacitive sensor adapted to measure at least one of position, velocity and acceleration of the coil assembly with respect to the magnetic housing; and wherein the magnetic core comprises a wall defining a third cavity, and the coil assembly has formed thereon an insulated rod that extends from an interior surface of the coil assembly into the third cavity, wherein the insulated rod has disposed thereon a pair of electrically conductive areas that form a capacitor with each other and form respective capacitors with the wall of the magnetic core, thereby forming the capacitive sensor.