Focused acoustic radiation for rapid sequential ejection of subwavelength droplets
AssigneeLabcyte Inc.
InventorRichard G. Stearns
Life of this patent
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Abstract
Focused acoustic radiation, referred to as tonebursts, are applied to a volume of liquid to generate a set of droplets. In one embodiment, a first toneburst is applied to temporarily raise a mound or protuberance on a free surface of the fluid. After the mound has reached a certain state, at least two additional toneburst can be applied to the protuberance to sequentially eject multiple bursts of multiple droplets. In one embodiment, the state of the mound can be maintained by a sustained acoustic signal, during which time multiple additional tonebursts can be applied to sequentially eject multiple bursts of multiple droplets from the mound.
Claims18
A method of ejecting droplets from a fluid in a reservoir, the method comprising:
- applying a stabilizing acoustic waveform to the fluid to stabilize a fluid mound on a free surface of the fluid;
- applying an electric field near the fluid;
- applying an ejection toneburst to the fluid mound during a period of time occurring while the fluid mound is stabilized by the stabilizing acoustic waveform, the ejection toneburst generating from the fluid mound a plurality of droplets, at least a portion of the plurality of droplets having net free charges;
- and
- controlling a center frequency of the stabilizing acoustic waveform to control a size of the fluid mound or sizes of the plurality of droplets or both.
A droplet ejection system configured to eject droplets from a free surface of a fluid in a fluid reservoir, the system comprising:
- an acoustic ejector comprising a transducer configured to be positioned opposite the free surface of the fluid in the fluid reservoir;
- an electrode positioned above the free surface of the fluid;
- and
- a controller comprising a processor and memory storing executable instructions that, when executed by the processor, cause the controller to perform operations including:
- applying, by the acoustic ejector, a stabilizing acoustic waveform to stabilize a fluid mound on the free surface of the fluid in the fluid reservoir;
- applying, by the electrode, an electric field near the fluid;
- applying, by the acoustic ejector, an ejection toneburst to the fluid mound during a period of time occurring while the fluid mound is stabilized by the stabilizing acoustic waveform, the ejection toneburst configured to eject from the fluid mound a plurality of droplets, at least a portion of the plurality of droplets having net free charges;
- and
- controlling a center frequency of the stabilizing acoustic waveform to control a size of the fluid mound or sizes of the plurality of droplets or both.
A method of ejecting droplets from a fluid in a reservoir, the method comprising:
- raising a fluid mound on a free surface of the fluid by applying a mound-raising toneburst of focused acoustic radiation to the fluid in the reservoir;
- applying an electric field near the fluid;
- applying an ejection toneburst to the fluid mound prior to collapse of the fluid mound on the free surface of the fluid, the ejection toneburst generating from the fluid mound a plurality of droplets, at least a portion of the plurality of droplets having net free charges, wherein the ejection toneburst is applied before the fluid mound has reached a maximum height;
- and
- controlling a center frequency of the mound-raising toneburst of focused acoustic radiation to control a size of the fluid mound or sizes of the plurality of droplets or both.
Dependencies are inferred from the claim text.