Acoustically ejecting a droplet of fluid from a reservoir by an acoustic fluid ejection apparatus

摘要

The invention provides apparatuses and methods for acoustically ejecting the fluid from a reservoir contained in or disposed on a substrate. The reservoir has a portion adapted to contain a fluid, and an acoustic radiation generator is positioned in acoustic coupling relationship to the reservoir. Acoustic radiation generated by the acoustic radiation generator is transmitted through at least the portion of the reservoir to an analyzer. The analyzer is capable of determining the energy level of the transmitted acoustic radiation and raising the energy level of subsequent pulses to a level sufficient to eject fluid droplets from the reservoir. The invention is particularly suited for delivering fluid from a plurality of reservoirs in an accurate and efficient manner.

主权项

1. An apparatus for acoustically ejecting a droplet of fluid from each of a plurality of reservoirs comprising:
a plurality of fluid reservoirs contained in or located on a substrate; a quantity of fluid disposed in each reservoir of the plurality of fluid reservoirs; an acoustic radiation generator for generating at least one pulse of acoustic radiation; a means for successively acoustically coupling the acoustic radiation generator with each reservoir such that at least one pulse of acoustic radiation generated by the acoustic radiation generator is transmitted through the substrate and into the fluid to a site at or near the surface of the fluid in each reservoir in a manner effective to eject a droplet from each reservoir acoustically coupled to the acoustic radiation generator; and an analyzer for determining, prior to acoustically ejecting a droplet of fluid from a reservoir, the wave form of a droplet-forming pulse of acoustic radiation to be generated, wherein the analyzer is further configured to determine an amplitude for the droplet-forming pulse which is sufficient to eject a fluid droplet; wherein the analyzer is further configured to, for determining the amplitude for the droplet-forming pulse for a reservoir:
(i) acoustically couple an acoustic ejector with the reservoir;(ii) activate the acoustic ejector to generate and direct a perturbation pulse into the reservoir such that the surface of the fluid is disturbed but no fluid droplet is ejected;(iii) generate a perturbation interrogation pulse directed at the surface of the fluid;(iv) detect a reflection of the perturbation interrogation pulse from the surface of the fluid; and(v) process the reflection detected in step (iv); wherein the processing of step (v) includes analyzing the frequency spectrum of a portion of the reflection detected in step (iv); wherein the processing of step (v) includes using a frequency domain-based algorithm to identify the difference in frequency between two minima of the frequency spectrum of the reflection detected in step (iv).