Differentially-driven MEMS spatial light modulator
First Claim
1. In a spatial light modulator having a plurality of pixels, an electrostatic actuator associated with a pixel and comprising:
- a lower electrode;
an upper electrode fixed with respect to the lower electrode;
a center electrode suspended and actuable between the upper and lower electrodes, and having resiliently-biasing means for restoring the center electrode to a non-actuated first equilibrium position;
a mirror operably connected to the center electrode;
a first voltage source for providing a first bias voltage across the lower and center electrodes;
a second voltage source for providing a second bias voltage across the upper and center electrodes, wherein the first and second bias voltages determine the non-actuated first equilibrium position of the center electrode; and
a third voltage source for providing a variable driver voltage across one of the lower/center and upper/center electrode pairs in series with the corresponding first or second bias voltage, for actuating the center electrode to a dynamic second equilibrium position.
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Abstract
A MEMS SLM and an electrostatic actuator associated with a pixel in an SLM. The actuator has three electrodes: a lower electrode; an upper electrode fixed with respect to the lower electrode; and a center electrode suspended and actuable between the upper and lower electrodes. The center electrode is capable of resiliently-biasing to restore the center electrode to a non-actuated first equilibrium position, and a mirror is operably connected to the center electrode. A first voltage source provides a first bias voltage across the lower and center electrodes and a second voltage source provides a second bias voltage across the upper and center electrodes, with the first and second bias voltages determining the non-actuated first equilibrium position of the center electrode. A third voltage source provides a variable driver voltage across one of the lower/center and upper/center electrode pairs in series with the corresponding first or second bias voltage, to actuate the center electrode to a dynamic second equilibrium position.
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Citations
27 Claims
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1. In a spatial light modulator having a plurality of pixels, an electrostatic actuator associated with a pixel and comprising:
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a lower electrode;
an upper electrode fixed with respect to the lower electrode;
a center electrode suspended and actuable between the upper and lower electrodes, and having resiliently-biasing means for restoring the center electrode to a non-actuated first equilibrium position;
a mirror operably connected to the center electrode;
a first voltage source for providing a first bias voltage across the lower and center electrodes;
a second voltage source for providing a second bias voltage across the upper and center electrodes, wherein the first and second bias voltages determine the non-actuated first equilibrium position of the center electrode; and
a third voltage source for providing a variable driver voltage across one of the lower/center and upper/center electrode pairs in series with the corresponding first or second bias voltage, for actuating the center electrode to a dynamic second equilibrium position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A spatial light modulator (SLM) comprising:
an array of electrostatic actuators, each representing a pixel of the SLM and comprising;
a lower electrode;
an upper electrode fixed with respect to the lower electrode;
a center electrode suspended and actuable between the upper and lower electrodes, and having resiliently-biasing means for restoring the center electrode to a non-actuated first equilibrium position;
a mirror operably connected to the center electrode;
a first voltage source for providing a first bias voltage across the lower and center electrodes;
a second voltage source for providing a second bias voltage across the upper and center electrodes, wherein the first and second bias voltages determine the non-actuated first equilibrium position of the center electrode; and
a third voltage source for providing a variable driver voltage across one of the lower/center and upper/center electrode pairs in series with the corresponding first or second bias voltage, for actuating the center electrode to a dynamic second equilibrium position. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A MEMS electrostatic actuator comprising:
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a first electrode layer;
a second electrode layer fixed with respect to the first electrode layer;
a center electrode layer suspended and actuable between the first and second electrode layers and having resiliently-biasing means for restoring the center electrode layer to a non-actuated first equilibrium position;
a first voltage source for providing a first bias voltage across the first and center electrode layers;
a second voltage source for providing a second bias voltage across the second and center electrode layers, wherein the first and second bias voltages determine the non-actuated first equilibrium position of the center electrode layer; and
a third voltage source for providing a variable driver voltage across one of the first/center and second/center electrode layer pairs in series with the corresponding first or second bias voltage, for actuating the center electrode layer to a dynamic second equilibrium position.
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26. A process for controlling a spatial light modulator (SLM) comprising the steps of:
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providing a SLM having a plurality of electrostatic actuators, each actuator having a lower electrode, an upper electrode fixed with respect to the lower electrode, a center electrode suspended and actuable between the upper and lower electrodes with resiliently-biasing means for restoring the center electrode to a non-actuated first equilibrium position, and a mirror operably connected to the center electrode;
for each electrostatic actuator, (a) providing a first bias voltage across the lower and center electrodes, and a second bias voltage across the upper and center electrodes, to establish the corresponding non-actuated first equilibrium position; and
(b) applying a variable driver voltage across one of the lower/center and upper/center electrode pairs in series with the corresponding first or second bias voltage to actuate the center electrode to a dynamic second equilibrium position, wherein the variable driver voltage is applied independent of other actuators.
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27. An electrostatic actuation process comprising:
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providing first and second electrodes fixed relative to each other and a center electrode suspended and actuable between the first and second electrodes, the center electrode having resiliently-biasing means for restoring the center electrode to a non-actuated first equilibrium position;
providing a first bias voltage across the first and center electrodes, and a second bias voltage across the second and center electrodes to establish the non-actuated first equilibrium position; and
actuating the center electrode to a second dynamic equilibrium position by applying a variable driver voltage across one of the first/center and second/center electrode pairs in series with the corresponding first or second bias voltage.
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Specification