Valves and valve actuation – Heat or buoyancy motor actuated
Reexamination Certificate
1999-11-30
2001-09-04
Shaver, Kevin (Department: 3754)
Valves and valve actuation
Heat or buoyancy motor actuated
C251S063000, C251S129010, C417S379000
Reexamination Certificate
active
06283440
ABSTRACT:
BRIEF DESCRIPTION OF THE INVENTION
This invention relates generally to Micro-Electro Mechanical Systems (MEMS). More particularly, this invention relates to a Micro-Electro Mechanical block with controlled movement for regulating fluid flow.
BACKGROUND OF THE INVENTION
Micro-Electro Mechanical Systems (MEMS), which are sometimes called micromechanical devices or micromachines, are three-dimensional objects having one or more dimensions ranging from microns to millimeters in size. The devices are generally fabricated utilizing semiconductor processing techniques, such as lithographic technologies.
Generating effective actuation in a fluidic environment is challenging, as standard MEMS actuation methods are generally ineffective in this environment. For example, electrostatic actuators, such as an electro-static comb drive, will not function with a conducting dielectric, such as water. Thermal actuators, such as thermal bimorph actuators, are of limited value, as the boiling point of the surrounding fluid limits the thermal range of the device. Piezoelectric actuators have been used to some effect in micro-fluidic devices. However, these actuators have limited actuation range and are difficult to fabricate.
It would be highly desirable to generate actuation in a fluidic environment for applications such as flow regulation, stirring, positioning of mirrors within a flow stream, moving cells or biological samples, etc. It would be highly desirable to provide an actuator with large actuation ranges, which requires minimal energy to generate displacement, which requires little or no energy to maintain a given displacement, and which requires minimal energy to return to its initial configuration. Ideally, such an actuator could be constructed using standard MEMS fabrication techniques.
SUMMARY OF THE INVENTION
One embodiment of the invention is a Micro-Electro Mechanical device with a movable mechanical structure and a bias mechanism. A bubble confinement region is defined by at least a portion of the movable mechanical structure. A bubble generation mechanism produces a bubble within the bubble confinement region. The bubble displaces the movable structure and alters the configuration of the bias mechanism, thereby producing useful work.
Another embodiment of the invention is a Micro-Electro Mechanical flow regulator with a moving mechanical structure and a bias mechanism configured to selectively alter the position of the movable mechanical structure, thereby regulating flow.
Still another embodiment of the invention is a Micro-Electro Mechanical flow regulator with an inlet port; an outlet port; a control port; and a mechanical structure selectively obstructing the inlet port in response to a controlled pressure applied to the control port, thereby regulating flow from the inlet port to the outlet port.
Another embodiment of the invention is a method of regulating fluid flow. The method includes the steps of forming a bubble, altering the position of a mechanical structure in response to the bubble, eliminating the bubble, and responding to the eliminating step by changing the position of the mechanical structure, the mechanical structure thereby regulating fluid flow.
Advantageously, the invention establishes a fluid flow regulator with an actuator that has large actuation ranges. The actuator requires minimal energy to generate displacement, requires little or no energy to maintain displacement, and requires minimal energy to return to its initial configuration. Advantageously, the flow regulator of the invention is constructed using standard fabrication techniques.
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Keasel Eric
Pennie & Edmonds LLP
Shaver Kevin
The Regents of the University of California
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