Systems, devices, and methods for driving an interferometric modulator

Abstract

This disclosure provides systems, methods, and apparatus for controlling the actuation of an analog interferometric modulator. In one aspect, a voltage may be determined from a sense electrode. A distance between one or more of the electrodes may be determined based on the voltage. The sense electrode may be capacitively coupled to another electrode, and may be implemented in a mirror of a movable layer of an interferometric modulator, or may be implemented in a floating fixed layer of an interferometric modulator.

What is claimed is: 
     
         1 . A device for modulating light, comprising:
 a first electrode coupled to a first voltage source;   a second electrode coupled to a capacitor;   a movable electrode disposed between and spaced apart from the first electrode and the second electrode, the movable electrode including a third electrode;   a voltage sensor coupled to the second electrode; and   a second voltage source coupled to the movable electrode.   
     
     
         2 . The device of  claim 1 , wherein the voltage sensor provides feedback for the second voltage source. 
     
     
         3 . The device of  claim 1 , wherein the movable electrode includes a mirror layer. 
     
     
         4 . The device of  claim 3 , wherein the second electrode includes a partially reflective layer. 
     
     
         5 . The device of  claim 1 , wherein the first voltage source includes a substantially fixed voltage source. 
     
     
         6 . The device of  claim 1 , wherein the second voltage source includes a variable voltage source. 
     
     
         7 . The device of  claim 6 , further including a drive circuit configured to adjust a position of the movable electrode by varying the voltage supplied by the second voltage source. 
     
     
         8 . The device of  claim 7 , wherein the drive circuit is coupled to a first bus connected to one or more voltage sensors of other devices for modulating light. 
     
     
         9 . A display system comprising the 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.   
     
     
         10 . The display system as recited in  claim 9 , further comprising:
 a driver circuit configured to send at least one signal to the display.   
     
     
         11 . The display system as recited in  claim 10 , further comprising:
 a controller configured to send at least a portion of the image data to the driver circuit.   
     
     
         12 . The display system as recited in  claim 9 , further comprising:
 an image source module configured to send the image data to the processor.   
     
     
         13 . The display system as recited in  claim 12 , wherein the image source module includes at least one of a receiver, transceiver, and transmitter. 
     
     
         14 . The display system as recited in  claim 9 , further comprising:
 an input device configured to receive input data and to communicate the input data to the processor.   
     
     
         15 . A method of driving a device for modulating light, comprising:
 applying a first voltage to a first electrode;   applying a second voltage to a movable electrode positioned between the first electrode and a second electrode, wherein the second electrode is coupled to a capacitor; and   sensing a voltage of the second electrode.   
     
     
         16 . The method of  claim 15 , wherein the movable electrode is displaced in response to the applying the second voltage. 
     
     
         17 . The method of  claim 16 , wherein the sensed voltage is used to adjust the applied second voltage until the offset of the movable electrode is substantially equal to a desired offset. 
     
     
         18 . A device for modulating light, comprising:
 means for applying a first voltage to a first electrode;   means for applying a second voltage to a movable electrode positioned between the first electrode and a second electrode, wherein the second electrode is coupled to a capacitor; and   means for sensing a voltage of the second electrode.   
     
     
         19 . The device of  claim 18 , additionally including means for determining a position of the movable electrode based at least in part on the sensed voltage.