AM-EWOD device and method of driving with variable voltage AC driving

1. An active matrix electrowetting on dielectric (AM-EWOD) device comprising:

a substrate electrode;

a plurality of array elements, each array element including an array element electrode;

first circuitry configured to supply a first time varying signal V 1 to at least a portion of the array element electrodes; and

second circuitry configured to supply a second time varying signal V 2 to the substrate electrode;

wherein an actuation voltage is defined by a potential difference between V 2 and V 1 , and the first circuitry further is configured to adjust the amplitude of V 1 to adjust the actuation voltage;

wherein the first circuitry is configured to adjust the amplitude of V 1 between a first amplitude V 1 A and a second amplitude V 1 B, wherein V 1 A is greater than V 1 B, and V 1 A is associated with a high voltage mode of operation and V 1 B is associated with a low voltage mode of operation; and

wherein the first circuitry comprises a signal generation circuit that is configured to adjust the first time varying signal V 1 spatially, and the signal generation circuit spatially adjusts the first time varying voltage V 1 by supplying a voltage having a first amplitude V 1 A to a first portion of the plurality of array element electrodes, and supplying a voltage having a second amplitude V 1 B to a second portion of the plurality of array element electrodes.

2. The AM-EWOD device of claim 1 , wherein the first circuitry is further configured to adjust the amplitude of the first time varying signal V 1 from V 1 A to V 1 B by applying a DC voltage V R to the first time varying signal.

3. The AM-EWOD device of claim 2 , wherein the DC voltage V R is adjustable to achieve different amplitude levels of V 1 B.

4. The AM-EWOD device of claim 1 , wherein the first circuitry is configured to adjust the first time varying signal V 1 temporally;

wherein the first circuitry temporally adjusts the first time varying voltage V 1 by supplying a voltage having a first amplitude V 1 A to the plurality of array element electrodes at a first time t 1 , and supplying a voltage having a second amplitude V 1 B to the plurality of array element electrodes at a second time t 2 ; and

the AM-EWOD device performs a first droplet manipulation operation at the time t 1 and a second droplet manipulation operation at the time t 2 .

5. The AM-EWOD device of claim 1 , wherein the first portion of the plurality of array element electrodes is a first zone of operation for performing a first droplet manipulation operation, and the second portion of the plurality of array element electrodes is a second zone of operation for performing a second droplet manipulation operation.

6. The AM-EWOD device of claim 5 , wherein the first zone of operation is a high voltage zone of operation, and the second zone of operation is a low voltage zone of operation.

7. The AM-EWOD device of claim 1 , wherein the signal generation circuit comprises:

a first level shifter circuit to supply the voltage having the first amplitude V 1 A to the first portion of the plurality of array element electrodes; and

a second level shifter circuit to supply the voltage having the second amplitude V 1 B to the second portion of the plurality of array element electrodes.

8. The AM-EWOD device of claim 1 , wherein the first circuitry and the second circuitry are configured such that the first circuitry adjusts the amplitude of V 1 while the second circuitry controls the amplitude of V 2 to remain unchanged.

9. The AM-EWOD device of claim 1 , further comprising:

thin film electronics that includes the first circuitry and the second circuitry;

a substrate upon which the thin film electronics is disposed;

external drive electronics configured to drive the first circuitry and the second circuitry of the thin film electronics;

sensor circuitry configured to implement feedback control of the external drive electronics; and

a non-transitory computer readable medium storing a computer program that is executed to control the external drive electronics.

10. A method of controlling an actuation voltage to be applied to a plurality of array elements of an active matrix electrowetting on dielectric (AM-EWOD) device, the AM-EWOD device having a substrate electrode and a plurality of array elements, each array element including an array element electrode;

wherein the actuation voltage is defined by a potential difference between the substrate electrode and the array element electrodes;

the method of controlling the actuation voltage comprising the steps of:

supplying a first time varying signal V 1 to at least a portion of the array element electrodes;

supplying a second time varying signal V 2 to the substrate electrode; and

controlling the actuation voltage by adjusting the amplitude of V 1 to adjust the actuation voltage;

wherein the amplitude of V 1 is adjusted between a first amplitude V 1 A and a second amplitude V 1 B;

V 1 A is greater than V 1 B;

and V 1 A is associated with a high voltage mode of operation and V 1 B is associated with a low voltage mode of operation; and

wherein the first time varying signal V 1 is adjusted spatially by a signal generation circuit supplying a voltage having a first amplitude V 1 A to a first portion of the plurality of array element electrodes, and supplying a voltage having a second amplitude V 1 B to a second portion of the plurality of array element electrodes.

11. The method of controlling an actuation voltage of claim 10 , wherein the amplitude of the first time varying signal V 1 is adjusted from V 1 A to V 1 B by applying a DC voltage V R to the first time varying signal.

12. The method of controlling an actuation voltage of claim 11 , wherein the DC voltage V R is adjustable to achieve different amplitude levels of V 1 B.

13. The method of controlling an actuation voltage of claim 10 , wherein:

the first time varying signal V 1 is adjusted temporally by supplying a voltage having a first amplitude V 1 A to the plurality of array element electrodes at a first time t 1 , and supplying a voltage having a second amplitude V 1 B to the plurality of array element electrodes at a second time t 2 ; and

the AM-EWOD device performs a first droplet manipulation operation at the time t 1 and a second droplet manipulation operation at the time t 2 .

14. The method of controlling an actuation voltage of claim 10 , wherein the first portion of the plurality of array element electrodes is a first zone of operation and the second portion of the plurality of array element electrodes is a second zone of operation;

the method further comprising performing a first droplet manipulation in the first zone of operation, and performing a second droplet manipulation in the second zone of operation.

15. The method of controlling an actuation voltage of claim 14 , wherein the first zone of operation is a high voltage zone of operation, and the second zone of operation is a low voltage zone of operation.

16. The method of controlling an actuation voltage of claim 12 , wherein the amplitude of V 1 is adjusted to adjust the actuation voltage while the amplitude of V 2 remains unchanged.