Backplanes with hexagonal and triangular electrodes
Active matrix backplanes including an array of hexagonal electrodes or an array of triangular electrodes. Because the backplane designs route the gate lines along the periphery of the electrodes there is less cross talk with the surface of the electrode. The disclosed designs simplify construction and control of the electrodes and improve the regularity of the electric field above the electrode. Such backplane electrode designs may be particularly useful in electrowetting on dielectric (EWoD) devices and electrophoretic displays (EPD).
1. A microfluidic device comprising:
a pixel electrode backplane defining a plurality of hexagonal cells comprising:
a plurality of scan lines;
a plurality of gate lines;
a plurality of storage capacitors having a capacitance greater than 0.5 pF;
a plurality of thin film transistors; and
a plurality of hexagonal propulsion electrodes having a dielectric coating over the plurality of hexagonal propulsion electrodes and a first hydrophobic layer disposed on the dielectric coating, the hexagonal propulsion electrodes being arranged in a honeycomb structure, and each hexagonal propulsion electrode being operatively coupled to a storage capacitor and a thin film transistor, wherein the voltage potential of each hexagonal propulsion electrode is controllable with only one scan line and only one gate line;
a light-transmissive electrode having a second hydrophobic layer disposed on the light-transmissive electrode;
an oil layer in contact with the first hydrophobic layer and the second hydrophobic layer; and
a spacer disposed between the pixel electrode backplane and the light-transmissive electrode,
wherein the microfluidic device is configured to move aqueous droplets distributed in the oil layer between three or more of the plurality of hexagonal cells.
2. The microfluidic device of claim 1 , wherein the plurality of scan lines is coupled to a scan controller, and the plurality of gate lines is coupled to a gate controller.
3. The microfluidic device of claim 2 , wherein the pixel electrode backplane is substantially rectangular in shape, and the scan controller is disposed along a first edge of the pixel electrode backplane and the gate controller is disposed along a second edge of the pixel electrode backplane.
4. The microfluidic device of claim 1 , wherein the gate lines are routed parallel to the edges of the hexagonal propulsion electrodes.
5. The microfluidic device of claim 4 , wherein the scan lines are routed perpendicular to the gate lines.
6. A microfluidic device comprising:
a pixel electrode backplane defining a plurality of triangular cells comprising:
a plurality of scan lines;
a plurality of gate lines;
a plurality of storage capacitors having a capacitance greater than 0.5 pF;
a plurality of thin film transistors; and
a plurality of triangular propulsion electrodes having a dielectric coating over the plurality of triangular propulsion electrodes and a first hydrophobic layer disposed on the dielectric coating, each triangular propulsion electrode being operatively coupled to a storage capacitor and a thin film transistor, wherein four triangular propulsion electrodes are arranged as a square and the voltage potential of each triangular propulsion electrode is controllable with only one scan line and only one gate line;
a light-transmissive electrode having a second hydrophobic layer disposed on the light-transmissive electrode;
an oil layer in contact with the first hydrophobic layer and the second hydrophobic layer; and
a spacer disposed between the pixel electrode backplane and the light-transmissive electrode,
wherein the microfluidic device is configured to move aqueous droplets distributed in the oil layer between three or more of the plurality of triangular cells.
7. The microfluidic device of claim 6 wherein the plurality of scan lines is coupled to a scan controller, and the plurality of gate lines is coupled to a gate controller.
8. The microfluidic device of claim 7 , wherein the pixel electrode backplane is substantially rectangular in shape, and the scan controller is disposed along a first edge of the pixel electrode backplane and the gate controller is disposed along a second edge of the pixel electrode backplane.
9. The microfluidic device of claim 6 , wherein the gate lines are routed parallel to the edges of the triangular electrodes.
10. The microfluidic device of claim 9 , wherein the scan lines are routed perpendicular to the gate lines.
11. The microfluidic device of claim 6 , wherein the scan lines are routed parallel to the edges of the triangular propulsion electrodes.