Actuator device based on an electroactive polymer

1. A device comprising:

an active matrix array of electroactive polymer actuators comprising:

a plurality of rows and a plurality of columns;

a set of data lines;

a set of addressing lines; and

a plurality of switching arrangements,

wherein each switching arrangement of the plurality of switching arrangements is associated with each electroactive polymer actuator of the electroactive polymer actuators,

wherein each switching arrangement comprises an input which is connected to a respective data line from the set of data lines, and an output which is connected to a first terminal of the associated electroactive polymer actuator, and

wherein a second terminal of each electroactive polymer actuator is connected to a control line, and

a driver circuit arranged to provide drive signals, the drive signals comprising at least a first drive level, a second drive level, a third drive level, and a fourth drive level, wherein the first drive level and the second drive level are for application to the set of data lines, and the third drive level and the fourth drive level are for application to the control line.

2. The device as claimed in claim 1 ,

wherein the active matrix array comprises a plurality of sub-arrays,

wherein there is a shared control line for each sub-array of the plurality of sub-arrays, and

wherein each sub-array comprises a row of the electroactive polymer actuators.

3. The device as claimed in claim 1 , wherein there is a shared control line for all of the electroactive polymer actuators.

4. The device as claimed in claim 1 ,

wherein the electroactive polymer actuators have a threshold voltage,

wherein each of the drive signals has a drive voltage,

wherein the drive voltage below the threshold voltage provides minimal actuation, and

wherein the drive voltage at a maximum drive voltage provides full actuation.

5. The device as claimed in claim 4 ,

wherein the first and third drive levels comprise 0V, and

wherein the fourth drive level comprises a voltage which is greater than a voltage of the second drive level.

6. The device as claimed in claim 5 ,

wherein the voltage of the fourth drive level is the maximum drive voltage, and

wherein a difference between the voltages of the second and fourth drive levels is equal to or less than the threshold voltage.

7. The device as claimed in claim 5 ,

wherein the voltage of the fourth drive level is a negative voltage of magnitude equal to or less than the threshold voltage, and

wherein the voltage of the second drive level is a positive voltage such that a difference between the voltages of the second and fourth drive levels is equal to the maximum drive voltage.

8. The device as claimed in claim 1 , wherein each switching arrangement of the plurality of switching arrangements comprises a transistor.

9. The device as claimed in claim 1 ,

wherein the active matrix array comprises a plurality of sub-arrays,

wherein there is a shared control line for each sub-array of the plurality of sub-arrays, and

wherein each sub-array comprises a column of the electroactive polymer actuators.

10. The device as claimed in claim 8 , wherein the transistor is selected from the group consisting of a thin film transistor, a polysilicon transistor, an amorphous silicon transistor, or a semiconductor oxide transistor.

11. A method of actuating a device, wherein the device comprises an active matrix array of electroactive polymer actuators, the active matrix array comprising a plurality of rows and a plurality of columns, wherein each electroactive polymer actuator of the electroactive polymer actuators is associated with a switching arrangement of a plurality of switching arrangements, wherein each of the plurality of switching arrangements comprises an input, which is connected to a respective data line, and an output, wherein the output is connected to a first terminal of the associated electroactive polymer actuator, and wherein a second terminal of each electroactive polymer actuator is connected to a control line, the method comprising:

setting all the electroactive polymer actuators to a non-actuated state using a third drive level, wherein the third drive level is provided on associated control lines;

driving all the electroactive polymer actuators towards a first state by providing a first drive level on associated data lines and a fourth drive level on the associated control lines; and

before the electroactive polymer actuators reach the first state, driving a portion of the electroactive polymer actuators to a second state by applying a second drive level on the associated data lines.

12. The method as claimed in claim 11 ,

wherein the electroactive polymer actuators have a threshold voltage,

wherein a drive voltage below the threshold voltage causes minimal actuation, and

wherein the drive voltage at a maximum drive voltage causes full actuation.

13. The method as claimed in claim 12 ,

wherein the first and third drive levels comprise 0V, and

wherein the fourth drive level comprises a voltage which is greater than a voltage of the second drive level.

14. The method as claimed in claim 13 ,

wherein the voltage of the fourth drive level is the maximum drive voltage, and

wherein a difference between the voltages of the second and fourth drive levels is equal to or less than the threshold voltage.

15. The method as claimed in claim 13 ,

wherein the voltage of the fourth drive level is a negative voltage of magnitude equal to or less than the threshold voltage, and

wherein the voltage of the second drive level is a positive voltage such that a difference between the voltages of the second and fourth drive levels is equal to the maximum drive voltage.