Piezoelectric dispenser with replaceable ampoule
Fluid delivery devices and methods are described, where the device may comprise a piezoelectric actuator operatively coupled to an ampoule with fluid, under a preloading force. The ampoule may comprise a thin-walled thermoplastic package which includes one or more apertures positioned on the wall of the ampoule. The piezoelectric actuator may be configured to clamp at least partially around the circumference of the ampoule and apply oscillations to its wall. The oscillations, typically in ultrasonic frequency, produce cycles of acoustic pressure in the fluid, leading to ejection of the fluid droplets or streams from the apertures.
1. A dispensing apparatus, comprising:
an actuator, and
an ampoule containing a liquid to be dispensed, the ampoule including a reservoir portion within which the fluid is contained, a neck portion extending from the reservoir portion, and a fluid path extending between the reservoir portion and neck portion to permit fluid from the reservoir to be directed to the neck portion;
wherein the neck portion includes at least one aperture through a side wall of the neck portion;
wherein the actuator engages with the neck portion via clamping, and wherein a clamping direction of the actuator is substantially perpendicular to a direction of fluid emission from the at least one aperture;
wherein the actuator is configured such that an oscillation of the actuator produces a corresponding oscillation of the neck portion in the direction of fluid emission from the at least one aperture, thereby emitting the liquid to be dispensed from the at least one aperture in a direction substantially perpendicular to the fluid path.
2. The apparatus of claim 1 wherein the neck portion has a cross-sectional shape selected from the group consisting of: circular, oval, triangular, square, pentagonal, hexagonal and octagonal.
3. The apparatus of claim 1 wherein the neck portion is secured to the actuator via an interference fit.
4. The apparatus of claim 1 wherein an operating frequency of the apparatus is near or at a resonance frequency of the actuator.
5. The apparatus of claim 1 wherein a clamping force of the actuator upon the neck portion is less than 5 N.
6. The apparatus of claim 1 wherein the actuator comprises a bending transducer configured to oscillate in a bending mode.
7. The apparatus of claim 6 wherein the bending transducer comprises a bimorph actuator having a first piezoceramic layer, a second piezoceramic layer, and a passive layer between the first and second piezoceramic layers.
8. The apparatus of claim 7 wherein the passive layer comprises a printed circuit board.
9. The apparatus of claim 6 wherein the bending transducer comprises a unimorph actuator having a piezoceramic layer.
10. The apparatus of claim 6 further comprising electronic circuitry programmed to drive the actuator.
11. The apparatus of claim 1 wherein an oscillation amplitude of the actuator is less than 2 micron.
12. The apparatus of claim 1 wherein the fluid comprises ophthalmic medication.
13. The apparatus of claim 1 further comprising an optical alignment system which enables a patient to align the at least one aperture to a targeted region on a surface of an eye of the patient.
14. The apparatus of claim 1 , wherein the direction of fluid emission is substantially horizontal.
15. The apparatus of claim 1 , wherein the fluid to be dispensed passes through a gap in the actuator as the fluid is dispensed through the aperture.
16. The apparatus of claim 1 , wherein the direction of fluid emission is substantially normal to a longitudinal axis of the neck portion.
17. The apparatus of claim 14 , wherein the direction of fluid emission is coplanar with a portion of the clamping direction.