Electrostatic levitation control system for micromechanical devices
AssigneePrinceton University
InventorsDong-Il D. Cho, Suresh Kumar, William N. Carr
Life of this patent
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Abstract
A mass to be levitated is provided with an electrically conductive surface that is acted upon by an oscillating electrical force field generated by a plurality of charged conductive plates. The levitated mass is kept in static equilibrium in the electric field by driving the resonant circuit with an applied time varying voltage that has a frequency greater than the natural frequency of the resonant circuit. Motion of the mass is accomplished by providing actuator elements that are selectively charged to attract the mass in a given direction. Alternatively, the mass may be moved by employing a plurality of levitation control circuits that are sequentially energized.
Claims22
A levitation structure comprising:
- a support made of an electrically non-conductive material;
- first and second spaced electrical conductors mounted on said support;
- a mass having a third electrical conductor mounted thereon freely positioned adjacent said first and second electrical conductors;
- circuit means connected to said first and second electrical conductors for forming a resonant circuit including said first, second and third conductors and having a natural frequency;
- and
- a voltage means for driving said circuit means with an oscillating voltage having a frequency greater than said natural frequency.
A levitation structure comprising:
- a support made of an electrically non-conductive material;
- first and second spaced electrical conductors mounted in a first plane on said support;
- a mass having a sheet of non-conductive material;
- third and fourth electrical conductors mounted on opposite sides of said sheet;
- fifth and sixth spaced electrical conductors mounted in a second plane on said support wherein said first and second planes are substantially parallel;
- said mass mounted between said first and second planes and said first, second and third conductors forming a first capacitance means and said fourth, fifth and sixth conductors forming a second capacitance means;
- first inductance means connected in series with said first capacitance means to form a first resonant circuit having a first natural frequency;
- second inductance means connected in a series with said second capacitance means to form a second resonant circuit having a second natural frequency;
- and
- voltage means for driving said resonant circuits with an oscillating voltage having a frequency greater than said natural frequencies.
A levitation structure comprising:
- a support made of an electrically non-conductive material;
- a plurality of electrical conductors mounted on said support;
- a mass having an electrical conductor means mounted thereon positioned adjacent said support;
- circuit means connected to said plurality of conductors on said support for forming a resonant circuit with the conductor on said mass and having a natural frequency;
- a voltage means for driving said circuit means with an oscillating voltage having a frequency greater than said natural frequency for causing said plurality of conductors on said support to attract the conductor means on said mass to levitate said mass in an equilibrium position;
- and
- motion means for selectively moving said mass with respect to said support.
Dependencies are inferred from the claim text.