Abstract:
A semiconductor structure includes a substrate, a sacrificial layer formed on or over the substrate, and a structural layer formed on or over the sacrificial layer. At least one opening is formed in the structural layer. At least one opening is formed in the sacrificial layer below the at least one opening in the structural layer. The at least one opening in the structural layer and the at least one opening in the sacrificial layer are at least partially filled with a filler material. At least one portion of the structural layer is removed to define at least one microstructure. The sacrificial layer is removed such that the at least one microstructure is released from the substrate and the filler material forms one or more protrusions on the at least one microstructure, and/or one or more anchors anchoring the at least one microstructure to the substrate.
Abstract:
A Coriolis effect device includes a housing defining an interior chamber having a central axis, an inlet, an outlet, a leading disc and a trailing disc. Each disc is supported for oscillatory movement within the interior chamber of the housing. The leading disc defines a leading flow path in fluid communication with the inlet and interior chamber, wherein a portion of the leading flow path extends radially with respect to the central axis. The trailing disc is axially spaced from the leading disc. The trailing disc defines a trailing flow path in fluid communication with the interior chamber and the outlet, wherein a portion of the trailing flow path extends radially with respect to the central axis. A phase difference between leading and trailing oscillating signals picked up from the disc movement can be used to determine a mass flow rate of fluid passing from the inlet to the outlet.
Abstract:
An optical cross-connect switch comprises a base (216), a flap (211) and one or more electrically conductive landing pads (222) connected to the flap (211). The flap (211) has a bottom portion that is movably coupled to the base (216) such that the flap (211) is movable with respect to a plane of the base (216) from a first orientation to a second orientation. The one or more landing pads (222) are electrically isolated from the flap (211) and electrically coupled to be equipotential with a landing surface.
Abstract:
A surface micromachining process for the fabrication of three-dimensional micro-hinges directly on silicon on insulator wafers. The process includes the steps of (a) defining openings around the surface of a desired hinge pin in a single layer of a silicon single crystal; (b) subjecting the openings to an etching process for removal of oxide material that is located in contiguous relation to the openings under the area of a hinge; (c) growing thermal oxide to define a gap between the hinge pin and a subsequently deposited polysilicon cap; (d) immediately depositing a thin layer of a chemical vapor deposited oxide sufficient to cover fine gaps not completely covered by the thermal oxide; depositing polysilicon and etching to define a hinge cap; and further etching to allow a mirror to be lifted out of the silicon wafer.
Abstract:
Health and usage monitoring systems for aircraft hoist systems are described herein. In some embodiments, a health and usage monitoring system comprises a capacitive load cell and a processing unit for communication with the capacitive load cell, the capacitive load cell comprising a load receiving surface and a capacitive assembly coupled to the load receiving surface, the capacitive assembly comprising parallel electrically conductive plates separated by a reversibly deformable spacer construction wherein the parallel plates comprise aligned apertures providing a passageway through the capacitive assembly for the hoist system cable.
Abstract:
The invention provides a sensor for determining when a latch for securing an engine cowl on an aircraft is secured by detecting the proximity of a latch hook and a latch pin. The sensor includes a resonant circuit configured and adapted to transmit a status signal when the latch is in a secured state. The sensor also includes a means for conveying status information of the latch to a location remote from the latch based on the status signal, the conveying means being operably connected to the resonant circuit. The invention also provides a method of determining when a latch is open or secured by detecting the proximity of a latch hook and a latch pin.
Abstract:
A monitoring system for a landing gear system comprising a plurality of sensors for monitoring respective parameters of the aircraft landing system, and a monitor which receives the outputs of the sensors.
Abstract:
An optical cross-connect switch comprises a base (216), a flap (211) and one or more electrically conductive landing pads (222) connected to the flap (211). The flap (211) has a bottom portion that is movably coupled to the base (216) such that the flap (211) is movable with respect to a plane of the base (216) from a first orientation to a second orientation. The one or more landing pads (222) are electrically isolated from the flap (211) and electrically coupled to be equipotential with a landing surface.
Abstract:
A method and apparatus are described for reducing stiction in a MEMS device having a movable element and a substrate. The method generally comprises providing the substrate with an anti-stiction member and interposing the anti-stiction member between the moveable element and the substrate. The apparatus generally comprises an anti-stiction member that is interposable between the moveable element and the substrate. Another embodiment of the invention of the invention is directed to a MEMS device, comprising: a substrate, a moveable element moveably coupled to the substrate, and an anti-stiction member that is interposable between the moveable element and the substrate. A further embodiment of the invention is directed to an optical switch having one or more moveable elements moveably coupled to a substrate, and an anti-stiction member that is interposable between at least one of the moveable elements and the substrate. The anti-stiction member may be in the form of a flexible cantilevered structure that overhangs the moveable element. Actuating the moveable element causes the anti-stiction member to flex and snap into place between the moveable element and the substrate. An additional embodiment of the invention is directed to a method of fabricating a MEMS device. The method proceeds by providing a silicon-on-insulator (SOI) substrate; defining a moveable element from a device layer of the SOI substrate; and depositing a flexible material over the device layer and the moveable element. One or more portions of the flexible material overhang the moveable element, whereby the flexible material forms one or more anti-stiction members.
Abstract:
A microelectromechanical systems (MEMS) element, MEMS optical switch and MEMS fabrication method are described. The MEMS element comprises a crystalline and moveable element is moveably attached to the substrate. The moveable element includes a perpendicular portion oriented substantially perpendicular to a plane of the substrate. The crystal structure of the perpendicular portion and substrate are substantially similar. The moveable element moveable is moveably attached to the substrate for motion substantially constrained to a plane oriented substantially perpendicular to a plane of the substrate. In at least one position, a part of a perpendicular portion of the moveable element projects beyond a surface of the substrate. The moveable element may be retained in place by a latch. The perpendicular portion may be formed substantially perpendicular portion to the substrate. An array of such structures can be implemented to work as an optical switch. The optical switch may comprise a crystalline substrate and one or more moveable elements moveably attached to the substrate. The MEMS elements may be fabricated by providing a substrate; forming one or more trenches in the substrate to define a perpendicular portion of a element; and moveably attaching the moveable element to a first surface of the substrate; removing a portion of the substrate such that at least a part of the perpendicular portion projects beyond a second surface of the substrate. The various embodiments provide for a robust and reliable MEMS elements that may be simply fabricated and densely packed.