Ultrasonic handpiece
View Patent ↗A handpiece having a single set of piezoelectric elements polarized to produce longitudinal motion when excited at the relevant resonant frequency. The piezoelectric crystals are connected to an ultrasonic horn to which a cutting tip is attached. The horn and/or the cutting tip contains a plurality of diagonal slits or grooves. The slits or grooves produce optimized torsional movement in the cutting tip when the piezoelectric crystals are excited at a second resonant frequency. Preferably, the two drive frequencies are not coincident, but provided in non-overlapping pulses.
1. An ultrasonic handpiece, comprising:
a) a handpiece shell;
b) an ultrasonic horn held within the shell, the horn containing a plurality of circumferential, diagonal slits sized and spaced so as to produce torsional movement in the horn in response to a drive signal having a first frequency and longitudinal movement in the horn in response to a drive signal having a second frequency; and
c) a plurality of piezoelectric elements;
wherein the piezoelectric elements and the horn are held within the shell so that a torsional nodal point and a proximal longitudinal nodal point are coincident at a plug that seals the shell on an end of the handpiece opposite a cutting tip.
2. The apparatus of claim 1 wherein the first drive signal and the second drive signal are alternated and do not overlap.
3. An ultrasonic handpiece comprising:
a handpiece shell;
an ultrasonic horn at least partially located in the shell, the horn having a plurality of slits sized and spaced so as to produce torsional movement in the horn in response to a drive signal having a first frequency and longitudinal movement in the horn in response to a drive signal having a second frequency;
a piezoelectric element connected to the horn; and
a plug that seals the shell on an end of the handpiece opposite a cutting tip;
wherein a torsional nodal point and a longitudinal nodal point are coincident at the plug.
4. The handpiece of claim 3 wherein the plurality of slits are spiral.
5. The handpiece of claim 3 wherein the plurality of slits are helical.
6. The handpiece of claim 3 further comprising:
an aspiration shaft extending through the horn.
7. The handpiece of claim 6 further comprising:
the cutting tip coupled o the aspiration shaft.
8. The handpiece of claim 3 wherein the horn has an outside diameter, and the width of the plurality of slits is between about 2% and 65% of the outside diameter of the horn.
9. The handpiece of claim 8 wherein the depth of the plurality of slits is between about 4% and 45% of the outside diameter of the horn.
10. The handpiece of claim 3 wherein the horn has a larger diameter, and the plurality of slits are between about 8% and 75% of the length of the larger diameter of the horn.
11. The handpiece of claim 10 wherein the pitch of the plurality of slits is between about 125% and 500% of the larger diameter of the horn.
12. The handpiece of claim 3 further comprising:
a drive circuit for driving the handpiece.
13. The handpiece of claim 3 wherein the first frequency is about 32 kHz.
14. The handpiece of claim 3 wherein the second frequency is about 44 kHz.
15. An ultrasonic handpiece comprising:
a handpiece shell;
be a plug that seals the shell on an end of the handpiece opposite a cutting tip;
an ultrasonic horn at least partially located in the shell and coupled to the shell at the plug, the horn having a plurality of slits sized and spaced so as to produce torsional movement in the horn in response to a drive signal having a first frequency and longitudinal movement in the horn in response to a drive signal having a second frequency; and
a piezoelectric element connected to the horn;
wherein a torsional nodal point and a longitudinal nodal point are coincident at the plug.
16. The handpiece of claim 15 wherein the horn is sealed to the shell at the plug location.
17. A phacoemulsification handpiece comprising:
a handpiece shell;
a horn at least partially located in the shell and sealed to the shell at a plug, the horn having a plurality of slits sized and spaced so as to produce torsional movement in the horn in response to a drive signal having a first frequency and longitudinal movement in the horn in response to a drive signal having a second frequency;
a tip coupled to the horn, the tip suitable for insertion into an eye, the tip configured to remove a lens from the eye when the tip is vibrated; and
a piezoelectric element coupled to the horn;
wherein a torsional nodal point and a longitudinal nodal point are coincident at the plug that seals the shell on an end of the handpiece opposite the tip.
18. The handpiece of claim 17 further comprising:
an aspiration shaft extending through the horn.
19. The handpiece of claim 17 further comprising:
a drive circuit for driving the piezoelectric element.
20. A phacoemulsification handpiece comprising:
a handpiece shell configured to be held in the hand;
a horn at least partially located in the shell, the horn having a plurality of slits sized and spaced so as to produce torsional movement in the horn in response to a drive signal having a first frequency and longitudinal movement in the horn in response to a drive signal having a second frequency;
a hollow tip coupled to the horn, the hollow tip suitable for insertion into an eye, the hollow tip configured to remove a lens from the eye when the hollow tip is vibrated;
an aspiration shaft extending through the horn;
a piezoelectric element coupled to the horn;
a drive circuit for driving the piezoelectric element; and
a plug that seals the shell on an end of the handpiece opposite the hollow tip;
wherein a torsional nodal point and a longitudinal nodal point are coincident at the plug.