Row and column actuator control
In one embodiment, a device is provided that includes: a plurality of actuators arranged into a plurality of rows and a plurality of columns; a plurality of row conductors corresponding to the plurality of rows; a plurality of column conductors corresponding to the plurality of columns; and a controller configured to select at least one of the actuators in a row by raising a voltage on the corresponding row conductor to couple each selected actuator to its corresponding column conductor.
1. A device comprising:
a cascaded electrostatic actuator including a stack of cells in a substrate, each cell having an isolated plate formed from a respective portion of the substrate, each isolated plate being surrounded by a corresponding gap between the isolated plate and another portion of the substrate; and
a controller configured to drive the cascaded electrostatic actuator to open and close selected ones of the gaps by asserting a voltage on selected ones of the isolated plates; and wherein
the portion of the substrate surrounding a corresponding isolated plate is deformed when the corresponding cell is actuated;
the isolated plates are arranged in a plurality of rows and a plurality of columns; and
the isolated plates of consecutive rows are arranged in a staggered configuration.
2. The device of claim 1 , further comprising:
a plurality of row conductors corresponding to the plurality of rows; and
a plurality of column conductors corresponding to the plurality of columns, wherein the controller is configured to drive the cascaded electrostatic actuator through the row and column conductors.
3. The device of claim 2 , further comprising:
a plurality of transistors defined in the substrate, the plurality of transistors corresponding to the plurality of isolated plates, wherein for each isolated plate, a gate for the corresponding transistor is driven by the corresponding row conductor, the transistor having a first terminal coupled to the corresponding column conductor and having a second terminal coupled to the isolated plate.
4. The device of claim 2 ,
wherein the cascaded electrostatic actuator is a parallel-plate actuator; and
wherein the row and column conductors are defined on separate layers with respect to the substrate.
5. The device of claim 4 , wherein the row and column conductors are polysilicon.
6. The device of claim 5 , wherein the row and column conductors are insulated from each other by an oxide layer.
7. The device of claim 2 , wherein the controller drives the row and column conductors through parallel interfaces.
8. The device of claim 2 , wherein the controller drives the row and column conductors through serial-to-parallel and parallel interfaces.
9. The device of claim 2 , wherein each gap completely surrounds the corresponding isolated plate.
10. The device of claim 1 , wherein the plurality of isolated plates in the stack are actuated to provide an aggregated travel distance or force in the stack.
11. The device of claim 1 , wherein the isolated plates of a first row have an overlap of approximately 50% with respect to the isolated plates of a second row adjacent to the first row.
12. The device of claim 1 , wherein the stack includes a plurality of conductors configured to enable each of the isolated plates to be independently actuated by the controller.
13. The device of claim 12 , wherein the controller is configured to vary the travel of the stack by actuating the isolated plates in different numbers of rows.
14. The device of claim 12 , wherein the controller is configured to cause the stack to curve by actuating more of the isolated plates in some columns than in other columns.
15. The device of claim 1 , wherein:
the amount of travel of the stack is proportional to the number of isolated plates in each of the plurality of columns; and
the force exerted by the stack is proportional to the number of isolated plates in each of the plurality of rows.
16. A device comprising:
a cascaded electrostatic actuator including a stack of cells in a substrate, each cell having an isolated plate formed from a respective portion of the substrate, each isolated plate being surrounded by a corresponding gap between the isolated plate and another portion of the substrate; and
means for independently and selectively actuating ones of the isolated plates to cause selected ones of the gaps to be opened or closed; and wherein
the portion of the substrate surrounding a corresponding isolated plate is deformed when the corresponding isolated plate is actuated;
the isolated plates are arranged in a plurality of rows and a plurality of columns; and
the isolated plates of consecutive rows are arranged in a staggered configuration.
17. The device of claim 16 , further comprising:
a plurality of row conductors corresponding to the plurality of rows; and
a plurality of column conductors corresponding to the plurality of columns, wherein the controller is configured to drive the cascaded electrostatic actuator through the row and column conductors; and wherein
each gap completely surrounds the corresponding isolated plate.
18. The device of claim 16 , wherein the isolated plates of a first row have an overlap of approximately 50% with respect to the isolated plates of a second row adjacent to the first row.
19. A cascaded electrostatic actuator comprising:
a conductive substrate having an array of electrostatic cells formed therein, each of the electrostatic cells including a peripheral wall and an open middle portion formed by a respective portion of the substrate;
a plurality of conductive isolated plates formed in the conductive substrate, each of the isolated plates being formed in the middle portion of an associated one of the electrostatic cells by another portion of the substrate such that a gap surrounds the isolated plate;
a plurality of control conductors selectively coupled to the plurality of isolated plates, each of the plurality of control conductors being configured to apply a voltage to an associated one of the isolated plates when selectively coupled thereto, whereby application of the voltage causes the substrate to deform and reduce the gap around at least a portion of the associated isolated plate, by creating an attractive force between the peripheral wall and the isolated plate; and wherein
the isolated plates are arranged in a plurality of rows and a plurality of columns; and
the isolated plates of consecutive rows are arranged in a staggered configuration.
20. The cascaded electrostatic actuator of claim 19 , further comprising:
a plurality of row conductors corresponding to the plurality of rows; and
a plurality of column conductors corresponding to the plurality of columns, wherein the controller is configured to drive the cascaded electrostatic actuator through the row and column conductors; and wherein
each gap completely surrounds the corresponding isolated plate.