The Research Of Phacoemulsification Handpiece

Phacoemulsification has become an important surgical treatment of cataract because of its small incision, quick healing, small astigmatism, fast postoperative visual acuity and small surgical damage. Phacoemulsification instrument, an important phacoemulsification auxiliary equipment, is made up of the ultrasonic generator and phacoemulsification handpiece. The phacoemulsification handpiece is the core component of the phacoemulsification instrument, its performance affects the effect of surgery directly. The phacoemulsification handpiece is mainly composed of the ultrasonic transducer and ultrasonic horn, and an emulsifying needle will be installed at the end when it works. Ultrasonic transducer is to convert electrical energy to mechanical vibration, but the amplitude of the radiation end surface is only a few microns. However, a few dozen to more than a hundred microns amplitude of the radiation end surface is required in the Cataract surgery, so a ultrasonic horn must be connected to the end of the transducer to amplify the amplitude. Angle from the ultrasonic transducer power to weight ratio requirements, always want to produce larger output energy to smaller weight. Therefore, the purpose of the subject is to seek a phacoemulsification handpiece that not only can meet the needs of the surgery, but also has a small size and light weight. In order to reduce the volume and mass of the handpiece, this paper presents the structure of1/4wavelength ultrasonic transducer plus1/4wavelength ultrasonic horn.Firstly, according to the variable cross-section thin rod and piezoelectric ceramics equivalent circuit derived the equivalent circuit of1/4wavelength sandwich ultrasonic transducer, and then designed28kHz and40kHz ultrasonic transducer by the equivalent circuit method. Then, using the analytical method designed1/4-wavelength stepped horn on the two frequencies, and the optimal circular arc of stepped ultrasonic horn was considered. Finally, analyzed the handpiece by modal analysis method and optimized the size of the handpiece loaded a needle in the finite element analysis software ANSYS11.0. Optimized handpiece harmonic response analysis and admittance research, drew a conclusion that though. the40kHz handpiece compared with the28kHz handpiece has lower piezoelectric conversion coefficient and smaller amplitude amplification factor, but it has smaller volume, mechanical loss and maximum stress, narrower frequency band, higher mechanical quality factor and acceleration. After adding needle on the two handpieces, the whole vibration system of two handpieces have considerable amplitude amplification factor, and the amplitude of the end of the needle are100μm or more, both can meet the needs of cataract surgery.40kHz handpiece can better meet the design requirements.