Microelectrofluidic device and method of driving the same
A microelectrofluidic device includes: a chamber; a first fluid and a second fluid which are contained in the chamber and are not mixable with each other; and a first electrode group including a plurality of electrodes that are disposed on an inner side of the chamber, and to which a voltage is applied to change an interface between the first fluid and the second fluid, wherein the plurality of electrodes are connected to form a first electrode unit, a second electrode unit, and a third electrode unit that are independently turned on or off, and the plurality of electrodes are annular and coated with an insulating material, and adjacent electrodes are connected to different electrode units.
1. A microelectrofluidic device comprising:
a chamber;
a first fluid and a second fluid which are contained in the chamber and are not mixable with each other; and
a first electrode group comprising a plurality of electrodes that are disposed on an inner side of the chamber, and to which a voltage is applied to change an interface between the first fluid and the second fluid,
wherein the plurality of electrodes are connected to form a first electrode unit, a second electrode unit, and a third electrode unit that are independently turned on or off, and
wherein the plurality of electrodes are annular and coated with an insulating material, and adjacent electrodes of the plurality of electrodes are connected to different electrode units.
2. The microelectrofluidic device of claim 1 , wherein the first electrode group has a single-layer array structure.
3. The microelectrofluidic device of claim 2 , wherein:
electrodes, among the plurality of electrodes, that are located in (3 k) th places in a direction away from a center of the first electrode group constitute a first electrode unit, where k is a natural number;
electrodes, among the plurality of electrodes, that are located in (3 k-1) th places from the center of the first electrode group constitute a second electrode unit; and
electrodes, among the plurality of electrodes, that are located in (3 k-2) th places (from the center of the first electrode group constitute a third electrode unit.
4. The microelectrofluidic device of claim 3 , wherein adjacent facing surfaces of the electrodes have uneven patterns.
5. The microelectrofluidic device of claim 3 , wherein the first fluid comprises a light-shielding material, the second fluid comprises a light-transmitting material, and a diameter of an aperture that transmits incident light is controlled according to a position change of the interface between the first fluid and the second fluid.
6. The microelectrofluidic device of claim 5 , wherein one of the first fluid and the second fluid comprises a polar material, and the other one of the first fluid and the second fluid comprises a non-polar material.
7. The microelectrofluidic device of claim 6 , wherein the chamber comprises:
a bottom substrate having an upper surface on which the first electrode group is disposed;
an intermediate plate that is disposed above and spaced apart from the bottom substrate, the intermediate plate comprises a first through-hole that forms a flow path for the first fluid at a center portion of the intermediate plate and a second through-hole that forms a flow path for the second fluid at a circumferential portion of the intermediate plate;
a top substrate that is disposed above and spaced apart from the intermediate plate; and
a spacer that surrounds a space formed between the bottom substrate and the top substrate.
8. The microelectrofluidic device of claim 7 , further comprising a second electrode group comprising a plurality of electrodes that are disposed on a lower surface of the intermediate plate, wherein the second electrode group has a single-layer array structure that is the same as that of the first electrode group.
9. The microelectrofluidic device of claim 7 , wherein an opaque pattern is formed on a center of a surface of the top substrate, wherein the opaque pattern shields light that has passed through the aperture.
10. The microelectrofluidic device of claim 7 , further comprising a ground electrode that is disposed on a surface of the bottom substrate, wherein the ground electrode contacts a polar fluid among the first fluid and the second fluid.
11. The microelectrofluidic device of claim 3 , wherein the first fluid and the second fluid comprise light-transmitting materials, each having a different refractive index,
the interface between the first fluid and the second fluid in the chamber comprises a first surface that constitutes a lens surface and a second surface that contacts the electrode group, and
according to how a voltage applied to the first electrode group is controlled, the position of the second surface is changed, thereby changing the curvature of the lens surface.
12. The microelectrofluidic device of claim 11 , wherein the first fluid comprises a polar material and the second fluid comprises a non-polar material.
13. The microelectrofluidic device of claim 11 , wherein the chamber comprises:
a bottom substrate having an upper surface on which the first electrode group is disposed;
an intermediate plate that is disposed above and spaced apart from the bottom substrate and comprises a first through-hole that forms a lens diameter corresponding to the lens surface at a center portion of the intermediate plate and a second through-hole that forms a flow path for the second fluid at a circumferential portion of the intermediate plate;
a top substrate that is disposed above and spaced apart from the intermediate plate; and
a spacer that surrounds a space formed between the bottom substrate and the top substrate.
14. The microelectrofluidic device of claim 13 , further comprising a second electrode group comprising a plurality of electrodes that are disposed on a lower surface of the intermediate plate, wherein the second electrode group has a single-layer array structure that is the same as that of the first electrode group.
15. The microelectrofluidic device of claim 13 , further comprising a ground electrode that is located on a surface of the bottom substrate, wherein the ground electrode contacts a polar fluid among the first fluid and the second fluid.
16. The microelectrofluidic device of claim 14 , further comprising a second intermediate plate interposed between the bottom substrate and the first intermediate plate, wherein the second intermediate plate comprises through-holes respectively corresponding to the first and second through-holes of the first intermediate plate.
17. The microelectrofluidic device of claim 16 , further comprising a third electrode group comprising a plurality of electrodes that are disposed on an upper or lower surface of the second intermediate plate, wherein the third electrode group has a single-layer array structure that is the same as that of the first electrode group.
18. A method of changing a location of an interface between a first fluid and a second fluid that are not mixable and are contained in a chamber of in a microelectrofluidic device, wherein the microfluidic device includes an electrode group including a plurality of electrodes that have different annular shapes and are spaced apart from each other, the method comprising:
controlling the electrodes to have a same voltage as any one of a first electrode unit, a second electrode unit, and a third electrode unit which are independently turned on or off, wherein adjacent electrodes among the electrodes are controlled according to different electrode units.
19. The method of claim 18 , wherein the electrode group has a single-layer array structure.
20. The method of claim 19 , wherein:
electrodes, among the plurality of electrodes, that are located in (3 k) th places in a direction away from the center of the electrode group are controlled according to the first electrode unit, where k is a natural number;
electrodes, among the plurality of electrodes, that are located in (3 k-1) th places from the center of the electrode group are controlled according to the second electrode unit; and
electrodes, among the plurality of electrodes, that are located in (3 k-2) th places from the center of the electrode group are controlled according to the third electrode unit.
21. The method of claim 20 , wherein the turning on or off of the first electrode unit, the second electrode unit, and the third electrode unit are simultaneously performed without transient switching.
22. The method of claim 21 , wherein the first fluid comprises a light-shielding material and the second fluid comprises a light-transmitting material, and according to the position of the interface between the first fluid and the second fluid, a diameter of an aperture that transmits incident light is controlled.
23. The method of claim 21 , wherein the first fluid and the second fluid comprise light-transmitting materials, each having a different refractive index,
the interface between the first fluid and the second fluid in the chamber comprises a first surface that constitutes a lens surface and a second surface that contacts the electrode group, and
according to how a voltage applied to the first electrode group is controlled, the position of the second surface is changed, thereby changing the curvature of the lens surface.