CIRCUITS AND METHODS FOR SWITCHING OF MEMS SYSTEMS
This disclosure provides systems, methods and apparatus for addressing an array of pixels in a display. In one aspect, an electromechanical device includes a movable element coupled between a first and second actuator, and a charge distribution circuit arranged to electronically couple the first actuator to the second actuator and capable of equalizing a potential between the first actuator and the second actuator. In certain implementation, a method for addressing an array of pixels in a display, where a given pixel in the array of pixels includes a light modulator coupled between first and second actuator capacitors, includes equalizing a potential between the first actuator capacitor and the second actuator capacitor prior to discharging and re-charging the actuator capacitors. Equalizing a potential may include transferring charge from one actuator capacitor to another actuator capacitor until the voltage across each actuator capacitor is approximately equal.
1 . An electromechanical device comprising:
a movable element being movably responsive to a first actuator and second actuator, the first actuator including a first capacitor and the second actuator including a second capacitor; and
a charge distribution circuit arranged to electronically couple the first capacitor to the second capacitor and capable of equalizing a potential between the first capacitor and second capacitor.
2 . The electromechanical device of claim 1 , wherein the charge distribution circuit includes a single switch.
3 . The electromechanical device of claim 1 , wherein the charge distribution circuit includes at least a first switch and a second switch.
4 . The electromechanical device of claim 3 , wherein the charge distribution circuit further comprises a voltage interconnect coupled to the first switch and the second switch.
5 . The electromechanical device of claim 1 , further comprising:
a display;
a processor that is configured to communicate with the display, the processor being configured to process image data; and
a memory device that is configured to communicate with the processor.
6 . The electromechanical device of claim 5 , further comprising:
a driver circuit configured to send at least one signal to the display; and
a controller configured to send at least a portion of the image data to the driver circuit.
7 . The electromechanical device of claim 5 , further comprising:
an image source module configured to send the image data to the processor, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.
8 . The electromechanical device of claim 5 , further comprising:
an input device configured to receive input data and to communicate the input data to the processor.
9 . A display comprising:
an array of pixels comprising, for each pixel, a first actuator capacitor, a second actuator capacitor and a light modulator being electronically coupled to the first and second actuator capacitors; and
a control matrix associated with the array of pixels including, for each pixel:
a charge distribution circuit arranged to electronically couple the first actuator capacitor to the second actuator capacitor, and equalize a potential between the first actuator capacitor and the second actuator capacitor.
10 . The display of claim 9 , wherein the charge distribution circuit includes a single switch.
11 . The display of claim 9 , wherein the charge distribution circuit includes at least a first switch and a second switch.
12 . The display of claim 11 , wherein the charge distribution circuit further comprises a voltage interconnect coupled to the first switch and the second switch.
13 . A method for addressing an array of pixels in a display wherein a given pixel includes a light modulator coupled between first and second actuator capacitors, the method comprising:
equalizing a first potential of the first actuator capacitor and a second potential of the second actuator capacitor;
loading data to the array of pixels; and
for a given pixel,
discharging the first actuator capacitor based on the data;
re-charging the second actuator capacitor to an actuation voltage based on the data; and
causing the light modulator to move in response to a potential difference between the light modulator and at least one of the first and second actuator capacitors.
14 . The method of claim 13 , wherein the potential between the first actuator capacitor and the second actuator capacitor is equalized prior to discharging the first actuator capacitor and prior to causing the light modulator to move.
15 . The method of claim 13 , wherein equalizing the potential between the first actuator capacitor and the second actuator capacitor comprises moving charge from a high level node to a low level node.
16 . The method of claim 13 , wherein equalizing the potential between the first actuator capacitor and the second actuator capacitor comprises applying a first voltage to both the first actuator capacitor and the second actuator capacitor.
17 . The method of claim 16 , wherein the first voltage is approximately half of the actuation voltage.
18 . The method of claim 13 , wherein discharging the first actuator capacitor comprises discharging approximately half of the actuation voltage.
19 . The method of claim 13 , wherein re-charging the second actuator capacitor comprises re-charging from approximately half of the actuation voltage.
20 . The method of claim 13 , wherein loading data to the array of pixels comprises setting a latch in a first state.