Patent ID: 7572242

Claim:
A method of operating an ultrasound handpiece, comprising the steps of: a) providing an ultrasound handpiece; b) providing an ultrasound drive circuit capable of producing an ultrasound drive signal; c) delivering the ultrasound drive signal to the ultrasound handpiece in a series of pulses so as to produce periodic ultrasound vibrations in the ultrasound handpiece, each period of ultrasound vibrations in the ultrasound handpiece being followed by a period of no ultrasound vibrations in the ultrasound handpiece; and d) varying the power level of the ultrasound vibrations in the ultrasound handpiece during the periodic ultrasound vibrations in the ultrasound handpiece wherein varying the power level of the ultrasound vibrations in the ultrasound handpiece comprises dividing the periodic ultrasound vibrations in the handpiece into at least a first, low power torsional pulse period to avoid repulsion of lens material, followed by a second, high power longitudinal pulse period.