Patent attributes
In one embodiments, a phacoemulsification apparatus includes a phacoemulsification probe including a horn, a needle mounted in the horn and configured for insertion into a lens capsule of a human eye, and a piezoelectric actuator configured to vibrate the horn and the needle and having a resonant frequency, a signal generator configured to generate a drive signal to drive a vibration of the piezoelectric actuator, phase detection circuitry configured to measure a phase difference between: a voltage across the piezoelectric actuator, and a current flowing through the piezoelectric actuator in response to the drive signal, and a controller configured to adjust a frequency of the drive signal so as to minimize the measured phase difference, whereby the piezoelectric actuator vibrates at the resonant frequency.
