Apparatus for manipulating droplets
An apparatus for manipulating droplets is provided. In one embodiment, the apparatus includes a substrate having electrodes and adjacent reference elements configured for manipulating a droplet on a surface of the substrate. Other embodiments having a top plate, a footprint, and a dielectric are also included.
1. An apparatus for manipulating droplets, the apparatus comprising a substrate comprising drive electrodes and adjacent reference elements configured for manipulating a droplet on a surface of the substrate, wherein
the reference elements comprise a two dimensional grid of conducting lines electrically and physically distinct from the drive electrodes;
the apparatus further comprises a plate spaced from the surface of the substrate by a distance to define a space between the plate and the surface of the substrate, wherein the distance is sufficient to contain a droplet disposed in the space; and
the plate comprises a hydrophobic plate surface facing the surface of the substrate.
2. The apparatus of claim 1 wherein one or more of the drive electrodes is:
(a) coupled to a source of potential; or
(b) floated.
3. The apparatus of claim 1 wherein the two dimensional grid of conducting lines is:
(a) coupled to a source of potential; or
(b) floated.
4. The apparatus of claim 1 wherein:
(a) one or more of the drive electrodes is:
(i) coupled to a source of potential; or
(ii) floated; and
(b) the two dimensional grid of conducting lines is:
(i) coupled to a source of potential which differs from the potential of (a); or
(ii) floated.
5. The apparatus of claim 1 comprising an array of the drive electrodes.
6. The apparatus of claim 1 wherein the drive electrodes and reference elements are in a substantially coplanar relationship.
7. The apparatus of claim 1 comprising drive electrodes covered by a dielectric layer.
8. The apparatus of claim 7 wherein at least a portion of the dielectric layer is hydrophobic.
9. The apparatus of claim 1 wherein at least outer portions of the drive electrodes and the reference elements are respectively hydrophobized.
10. The apparatus of claim 1 further comprising a hydrophobic film disposed on the drive electrodes and the reference elements.
11. The apparatus of claim 1 comprising a filler fluid disposed in the space.
12. The apparatus of claim 1 further comprising an electrode selector for sequentially activating and de-activating one or more selected drive electrodes of the array.
13. The apparatus of claim 12 wherein drive electrodes are arranged such that the sequentially activating and de-activating one or more selected drive electrodes of the array sequentially biases the selected drive electrodes to an actuation voltage such that a droplet disposed on the surface of the substrate moves along a path defined by the selected drive electrodes.
14. The apparatus of claim 12 wherein the two dimensional grid of conducting lines is set to a reference voltage less than the actuation voltage.
15. The apparatus of claim 12 wherein the two dimensional grid of conducting lines is set to ground potential.
16. The apparatus of claim 12 wherein the two dimensional grid of conducting lines is floated.
17. The apparatus of claim 12 wherein the electrode selector comprises an electronic processor.
18. The apparatus of claim 1 comprising a droplet inlet communicating with the surface.
19. The apparatus of claim 1 comprising a droplet outlet communicating with the surface.