Patent ID: 7307397

Claim:
A driving unit comprising: a moving element; an elastic body configured to support said moving element, said elastic body and said moving element constituting a resonance system in which kinetic energy of said moving element and elastic energy of said elastic body are conserved and converted to each other; a permanent magnet fixed on said moving element; an electromagnet disposed opposite to said permanent magnet, said electromagnet including a magnetic material and a coil wound around said magnetic material; a controller, said controller magnetizing said magnetic material by feeding a current through said coil, and giving a vibration force to said moving element by magnetic force acting between said magnetic material and said permanent magnet; wherein said controller comprises a current waveform decider and an alternating voltage output part, said current waveform decider calculating vibration force necessary for an intended motion of the moving element based on behavior of the moving element and determining a sawtooth current waveform to be fed through the coil so as to give the calculated vibration force to the moving element, said alternating voltage output part applying a voltage to said coil intermittently at intervals shorter than an application time of said sawtooth current waveform so that a current in a form of said sawtooth current waveform flows through said coil.