Patent ID: 11877953
Assignee: JOHNSON & JOHNSON SURGICAL VISION, INC.
Field: Medical technology (Instruments)
Classification: CPC A  G  H | IPC A  G  H

Claim 0:
1. A phacoemulsification apparatus comprising:
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, wherein the phase detection circuitry includes:
a first analog multiplier configured to perform a multiplication of the voltage with a reference signal yielding voltage resultant signals; and
a second analog multiplier configured to perform a multiplication of the current with the reference signal yielding current resultant signals; 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.