Droplet actuator structures
A droplet actuator comprising a substrate comprising an electrode coupled to a voltage source, wherein the droplet actuator is configured such that when voltage is applied to the electrode, an electrostatic energy gradient is established at a surface of the substrate which causes a droplet to be transported in a direction established by the energy gradient. Related methods and other embodiments are also provided.
1. A droplet actuator comprising:
a first substrate comprising a first plate and a second substrate comprising a second plate separated first plate by a gap wherein the first plate comprises an electrode configuration comprising electrodes arranged for conducting one or more droplet operations, the electrode configuration comprising:
a first electrode coupled to a voltage source, and first dielectric layer configuration comprising a first dielectric material layered above and along the length of the first electrode, the first dielectric material having a electrostatic energy gradient-establishing variation along the length of the electrode, wherein the droplet actuator is configured such that when voltage is applied to the first electrode, the electrostatic energy gradient is established at a surface of the first substrate along the length of the first electrode which causes a droplet to be transported along the length of the first electrode in a direction established by the energy gradient; and
a second electrode coupled to a second voltage source, and a second dielectric layer configuration comprising a second dielectric material layered above the second electrode, wherein the second dielectric layer configuration differs from the first dielectric layer configuration; and
wherein the second substrate lacks a dielectric material configured to establish a droplet-transporting energy gradient.
2. The droplet actuator of claim 1 wherein the first electrode is a two terminal electrode composed of a resistive material, such that the first electrode functions as a resistor with a spatial distribution of electric potential along its length.
3. The droplet actuator of claim 1 wherein the first electrode is coupled to a second voltage source.
4. The droplet actuator of claim 3 wherein the first voltage source and the second voltage source are actively applying voltage, and the voltages applied are actively establishing a voltage difference between the first and second voltage sources.
5. The droplet actuator of claim 4 wherein the voltage difference ranges from about >0 volts to about 300 volts.
6. The droplet actuator of claim 1 wherein the first electrostatic energy gradient results from a gradient in thickness of the material layered above the electrode.
7. The droplet actuator of claim 1 wherein the electrostatic energy gradient results from a gradient in dielectric constant of the dielectric material layered above the first electrode.
8. The droplet actuator of claim 1 wherein the electrostatic energy gradient results from a gradient in distance between the first electrode's surface and the surface of the first dielectric layer configuration.
9. The droplet actuator of claim 1 wherein the electrostatic energy gradient is continuous.
10. The droplet actuator of claim 1 wherein the electrostatic energy gradient is discontinuous.
11. The droplet actuator of claim 1 wherein the second dielectric material is layered above and along the length of the electrode, the second dielectric material having a difference in thickness along the length of the electrode, wherein the droplet actuator is configured such that when voltage is applied to the second electrode, an electrostatic energy gradient is established at a surface of the first substrate along the length of the second electrode which causes a droplet to be transported along the length of the second electrode in a direction established by the energy gradient.
12. The droplet actuator of claim 1 wherein the second electrode is a two terminal electrode composed of a resistive material, such that the electrode functions as a resistor with a spatial distribution of electric potential along its length.
13. The droplet actuator of claim 1 wherein the second electrode is coupled to a third voltage source in addition to the second voltage source.
14. The droplet actuator of claim 13 comprising a voltage difference between the second and third voltage sources.
15. The droplet actuator of claim 14 wherein the voltage difference ranges from about >0 volts to about 300 volts.
16. The droplet actuator of claim 1 wherein the second dielectric material layered above the second electrode comprises a difference in thickness comprises a gradient in thickness of the material layered above the electrode.
17. The droplet actuator of claim 1 wherein the second dielectric material layered above the second electrode comprises a gradient in dielectric constant.
18. The droplet actuator of claim 1 wherein the second dielectric material layered above the second electrode comprises a gradient in distance between the second electrode's surface and the surface of the second dielectric layer configuration.
19. The droplet actuator of claim 1 wherein the second dielectric material establishes an electrostatic energy gradient which is continuous.
20. The droplet actuator of claim 1 wherein the second dielectric material establishes an electrostatic energy gradient which is discontinuous.