Acoustic streaming fluid ejector

1. An acoustic streaming fluid ejector, comprising:

a fluid filled chamber having an opening;

a selectively vibrating flow generator having a sharp edge pointed toward the opening; and

a driving device configured to vibrate one of the flow generator and the chamber to create a streaming fluid flow in a direction away from the sharp edge through the opening.

2. The acoustic streaming fluid ejector of claim 1 , wherein the flow generator comprises two nonparallel surfaces forming an angle, the nonparallel surfaces being symmetrically disposed about an axis aligned with an axis through the opening.

3. The acoustic streaming fluid ejector of claim 2 , wherein the two nonparallel surfaces converge to form the sharp edge.

4. The acoustic streaming fluid ejector of claim 2 , wherein the sharp edge has an angle of 90 degrees or less.

5. The acoustic streaming fluid ejector of claim 1 , wherein the driving device is configured to vibrate the flow generator at the resonance frequency of the flow generator.

6. The acoustic streaming fluid ejector of claim 1 , wherein the driving device comprises one of piezoelectric stack and a coil.

7. The acoustic streaming fluid ejector of claim 1 , wherein the opening is disposed directly proximate the sharp edge of the flow generator.

8. The acoustic streaming fluid ejector of claim 1 , wherein the fluid is a drug for treating a condition.

9. The acoustic streaming fluid ejector of claim 1 , wherein the fluid is an ink.

10. The acoustic streaming fluid ejector of claim 1 , wherein the fluid is non-water soluble.

11. An acoustic streaming fluid ejector, comprising:

a fluid reservoir;

a fluid filled chamber in communication with the reservoir, the chamber having an opening;

a selectively vibrating flow generator having a sharp edge; and

a driving device configured to vibrate one of the flow generator and the chamber to create a streaming fluid flow in a direction away from the sharp edge in the chamber.

12. The acoustic streaming fluid ejector of claim 11 , wherein the flow generator comprises two nonparallel surfaces forming an angle, the nonparallel surfaces being symmetrically disposed about an axis aligned with an axis through the opening.

13. The acoustic streaming fluid ejector of claim 11 , wherein the sharp edge has an angle of 90 degrees or less.

14. The acoustic streaming fluid ejector of claim 11 , wherein the driving device is configured to vibrate the flow generator at the resonance frequency of the flow generator.

15. The acoustic streaming fluid ejector of claim 11 , wherein the driving device is a piezoelectric stack.

16. The acoustic streaming fluid ejector of claim 15 , wherein the two nonparallel surfaces converge to form the sharp edge.

17. The acoustic streaming fluid ejector of claim 11 , wherein the driving device is configured to vibrate the flow generator at the resonance frequency of the flow generator.

18. A method comprising:

providing a flow generator in a fluid-filled chamber having an opening, the flow generator having a sharp edge defined by two nonparallel surfaces forming an angle, the nonparallel surfaces being symmetrically disposed about an axis aligned with an axis through the opening; and

selectively vibrating the flow generator with a driving device to vibrate the sharp edge of the flow generator to eject a fluid droplet from the chamber and out of the opening.

19. The method of claim 18 , wherein vibrating the flow generator with a driving device comprises vibrating the flow generator with a piezoelectric stack.

20. The method of claim 18 , further comprising vibrating the flow generator at the resonance frequency of the flow generator.