Electrostatic micromotor
First Claim
1. An electrostatic machine comprising:
- a stator formed by surface micromachining sacrificial layers on a substrate surface;
a moveable member positioned for movement relative to the stator free of contact thereto, the moveable member formed and positioned with respect to the substrate surface during the surface micromachining that formed the stator;
means for generating and sustaining an electrostatic field about the moveable member across a gaseous gap between the stator and moveable member, facing surfaces of the surface micromachined stator and moveable member across the gaseous gap being free of contact with each other and sufficiently smooth to support a field strength above about 108 V/m without electrostatic breakdown, the distance between the stator and moveable member across the gaseous gap being about 5 micrometers or less.
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Accused Products
Abstract
An electrostatically driven microactuator is micromachined in a monolithic process. Sacrificial layers are placed between a moving element and stator structural layers. Removal of the sacrificial layers leaves a free standing moving element and micron wide air gaps within a stator. An electric field of about 100 Mv/m and higher is supported across the micron wide gap without breakdown and enables high energy torque densities to be produced between the stator and the moving element. One electrostatic drive scheme involves a series of stator electrodes attached to the stator and a series of electrodes attached to the moving element charged in sequence to attract each other in a direction of movement and to oppose each other in a direction normal to movement. A bearing is aligned with the moving element with the stator during the layering of a sacrificial layer over an edge of the moving element structural layer. The bearing and stator laterally stabilize the moving element. Vertical stability is through aerodynamic shaping of the moving element, electronic circuits, or bushings. Applications of the microactuator include a linearly sliding shutter, an optical modulator, a gyroscope and an air pump.
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Citations
27 Claims
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1. An electrostatic machine comprising:
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a stator formed by surface micromachining sacrificial layers on a substrate surface; a moveable member positioned for movement relative to the stator free of contact thereto, the moveable member formed and positioned with respect to the substrate surface during the surface micromachining that formed the stator; means for generating and sustaining an electrostatic field about the moveable member across a gaseous gap between the stator and moveable member, facing surfaces of the surface micromachined stator and moveable member across the gaseous gap being free of contact with each other and sufficiently smooth to support a field strength above about 108 V/m without electrostatic breakdown, the distance between the stator and moveable member across the gaseous gap being about 5 micrometers or less. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An electrostatic machine comprising:
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a stator formed by surface micromachining sacrificial layers on a substrate surface; a plate formed by the surface micromachining that formed the stator on the substrate surface and positioned for movement relative to the stator free of contact thereto and with a gaseous gap between the stator and plate, the distance across the gap between the stator and plate being short enough and facing surfaces of the stator and plate across the gap being smooth enough to support a field strength above about 108 V/m without electrostatic breakdown, the facing surfaces of the stator and plate being free of contact with each other across the gap, and the gap having a pressure-spacing of less than about 5×
10-3 bar mm; andmeans for generating and sustaining an electrostatic field across the gaseous gap between the stator and plate. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. An electrostatic machine comprising:
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a stator formed on a substrate surface; a moveable member positioned for movement relative to the stator over the substrate surface in a manner free of contact with the stator, the moveable member formed during the forming of the stator; means for generating an electrostatic field about the moveable member across a gaseous gap between the stator and moveable member in a manner which elevates the moveable member above the substrate surface and moves the elevated moveable member laterally over the substrate surface, the distance between the stator and moveable member across the gap being about 5 micrometers or less and surfaces of the stator and moveable member facing each other across the gap being free of contact with each other and smooth enough to support a field strength above about 108 V/m without electrostatic breakdown.
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27. An electrostatic machine comprising:
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a stator formed on a substrate surface; a plate positioned for movement relative to the stator in a manner free of contact thereto and with a gaseous gap between the stator and plate, the plate formed during the forming of the stator, the distance across the gap between the stator and plate being short enough and surfaces of the stator and plate facing each other across the gap being smooth enough to support a field strength above about 108 V/m without breakdown, the surfaces of the plate and stator facing each other across the gap being free of contact with each other, and the gap having a pressure-spacing less than about 5×
10-3 bar mm; andmeans for generating an electrostatic field across the gap between the stator and plate such that the plate is elevated above the substrate surface and moved laterally while being elevated.
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Specification