Patents by Inventor Dennis Greywall
Dennis Greywall has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Publication number: 20070126300Abstract: A reluctance motor having a movable part that does not need a fixed mounting shaft in the motor's stationary part. In one embodiment, a motor of the invention has a stationary part that defines a cylindrical cavity into which a rotor is inserted, with an interior wall of the cavity covered by nonmagnetic lining. The stationary part has a plurality of stator poles, each defined by an electric coil having a magnetic core. The rotor has a spacer and a plurality of bearings, with each bearing at least partially confined between the spacer and the lining. The rotor is adapted to spin within the cavity in response to the excitation of one or more of the stator poles such that the bearings roll between the lining and the spacer. The motor can be implemented as a MEMS device, with the motor's stator being a substantially monolithic structure formed using a single substrate, which structure has a size on the order of 1 mm.Type: ApplicationFiled: December 6, 2005Publication date: June 7, 2007Inventor: Dennis Greywall
-
Publication number: 20070068308Abstract: A rigid actuator arm is an appendage of a moveable drive plate that is coupled across at least one end of each of two deformable spring bars that are anchored at their opposite end to a support structure that keeps the end of the moveable drive plate that is not coupled to the to the deformable spring bars from touching the substrate. The moveable drive plate mates with an opposing fixed drive plate so that applying a potential difference between the moveable drive plate and the fixed drive plate causes the moveable drive plate to move toward the fixed drive plate with a rotation type motion. The rigid actuator arm likewise rotates about an axis that is through the point of attachment of the rigid actuator to the moveable drive plate. Consequently, the opposite end of the rigid actuator arm moves as well, with an amplification of the rotation motion.Type: ApplicationFiled: September 22, 2005Publication date: March 29, 2007Inventor: Dennis Greywall
-
Publication number: 20070058899Abstract: A MEMS device that enables an optical subsystem (e.g., an optical switch) having an optical component optically coupled to the MEMS device via free space to achieve optical alignment between the optical component and the MEMS device without moving the optical component with respect to the stationary part of the MEMS device. In one embodiment, a MEMS device of the invention has a stationary part and a movable part movably connected to the stationary part. The movable part has a platform and a plurality of mirrors mounted on the platform, wherein (i) each mirror is adapted to move with respect to the platform independent of other mirrors and (ii) the platform is adapted to move with respect to the stationary part together with the mirrors.Type: ApplicationFiled: September 13, 2005Publication date: March 15, 2007Inventors: Dennis Greywall, Dan Marom
-
Publication number: 20060228896Abstract: A method of fabricating a device using a multi-layered wafer that has an embedded etch mask adapted to map a desired device structure onto an adjacent (poly)silicon layer. Due to the presence of the embedded mask, it becomes possible to delay the etching that forms the mapped structure in the (poly)silicon layer until a relatively late fabrication stage. As a result, flatness of the (poly)silicon layer is preserved for the deposition of any necessary over-layers, which substantially obviates the need for filling the voids created by the structure formation with silicon oxide.Type: ApplicationFiled: March 31, 2005Publication date: October 12, 2006Inventor: Dennis Greywall
-
Publication number: 20060220492Abstract: A MEMS device having a movable plate supported on a substrate by a support structure that is hidden under the plate and yet which can be implemented to enable rotation of the plate with respect to the substrate about a rotation axis lying at the plate surface. As a result, the support structure does not take up any area within the plane of the plate, while enabling rotation of the plate, during which the plate does not substantially move sideways. The latter property reduces potential physical interference between neighboring plates in an arrayed MEMS device and enables implementation of a segmented mirror having relatively narrow gaps between adjacent segments and, thus, a relatively large fill factor, e.g., at least 98%.Type: ApplicationFiled: March 31, 2005Publication date: October 5, 2006Inventor: Dennis Greywall
-
Publication number: 20060181273Abstract: In one embodiment, an integrated magnetometer has a deformable, electrically conducting beam that is mounted on a substrate and adapted to oscillate with respect to the substrate. When the oscillating beam is exposed to a magnetic field, the magnetic field induces an oscillating electromotive force that generates an oscillating electrical signal along the beam. The magnetometer has a detection circuit that detects this oscillating electrical signal and, based on the results of this detection, determines the magnetic-field strength and/or the magnetic-field gradient.Type: ApplicationFiled: March 28, 2006Publication date: August 17, 2006Inventors: Dennis Greywall, Bernard Yurke
-
Publication number: 20060158484Abstract: A MEMS device having a fixed-fixed flexible beam, which is adapted to produce mechanical movement in response to a change of a temperature gradient and is relatively insensitive to variations in ambient temperature. In one embodiment, the flexible beam is connected between two support structures affixed to a substrate such that thermal deformation causes the beam to produce a displacement of its middle portion, thereby generating motion of a structure connected to that portion. In one embodiment, the structure includes (i) a plate having an IR-absorbing layer, which can transfer heat from IR radiation to the flexible beam, and (ii) an electrode layer, which together with a stationary electrode attached to the substrate forms a variable capacitor. Changes in the capacitance of the variable capacitor can be detected and related to the temperature of the IR-absorbing layer and/or intensity of the IR radiation impinging upon that layer.Type: ApplicationFiled: January 14, 2005Publication date: July 20, 2006Inventor: Dennis Greywall
-
Publication number: 20060066964Abstract: An array of high fill factor mirrors has each mirror be coupled across two deformable spring bars that are deformed using a drive. The two deformable springs are parallel to each other, and coupled together, e.g., by a cross bar. A support is coupled at one end to the cross bar and at its opposite end to the mirror. Coupled across the deformable spring bars on the opposite side thereof from the mirror support, is at least one moveable drive plate. Motion by the moveable drive plate causes the deformable spring bars to torque, e.g., in the local vicinity of the connection of the drive plate to the deformable spring bars. The torque causes the deformable spring bars to move downward, e.g., near their centers. As a result, cross bar, and hence the mirror, move downward.Type: ApplicationFiled: September 29, 2004Publication date: March 30, 2006Inventor: Dennis Greywall
-
Publication number: 20060066423Abstract: A MEMS device fabricated from a single multi-layered wafer, which alleviates the alignment problem associated with a two-piece prior-art design. In one embodiment, the MEMS device has a stationary part and a movable part rotatably coupled to the stationary part. The stationary part has an electrode and a first conducting structure electrically isolated from the electrode. The movable part has a rotatable plate and a second conducting structure located on the plate and electrically connected to the plate. The mass and location of the second conducting structure are selected such as to compensate for the plate's imbalance with respect to the rotation axis. In addition, at the rest position, the first and second conducting structures form, around the electrode, a substantially continuous barrier adapted to provide electrical shielding for the electrode.Type: ApplicationFiled: September 29, 2004Publication date: March 30, 2006Inventors: Dennis Greywall, Dan Marom
-
Publication number: 20060033585Abstract: In one embodiment, a magnetometer includes an electromechanical resonator coupled to a drive-and-detect (DD) circuit. The resonator has a deformable beam that is a part of a closed current path. By applying a periodic drive signal to a drive electrode located in proximity to the deformable beam, the DD circuit induces an oscillation of the beam. In the presence of a magnetic field, this oscillation changes the magnetic flux through the closed current path, thereby generating an oscillating electrical current in the path. Dissipation of this current due to resistive losses in the closed current path then dampens the oscillation of the deformable beam with a damping coefficient that depends on the magnetic-field strength. Using a sense electrode located in proximity to the deformable beam, the DD circuit detects the oscillation amplitude. Based on the detected amplitude, the DD circuit changes the frequency of the drive signal to find the resonant frequency.Type: ApplicationFiled: July 13, 2004Publication date: February 16, 2006Inventor: Dennis Greywall
-
Publication number: 20060033598Abstract: In one embodiment, an inertial switch of the invention includes a MEMS device manufactured using a layered wafer. The MEMS device has a movable electrode supported on a substrate layer of the wafer and a stationary electrode attached to that substrate layer. The movable electrode is adapted to move with respect to the substrate layer in response to an inertial force such that, when the inertial force per unit mass reaches or exceeds a contact threshold value, the movable electrode is brought into contact with the stationary electrode, thereby changing the state of the inertial switch from open to closed. In one embodiment, the MEMS device is a substantially planar device, designed such that, when the inertial force is parallel to the device plane, the displacement amplitude of the movable electrode from an initial position is substantially the same for all force directions. Advantageously, inertial switches of the invention can be designed to have a relatively small size, e.g.Type: ApplicationFiled: August 16, 2004Publication date: February 16, 2006Inventor: Dennis Greywall
-
Apparatus comprising an array of tightly spaced rotatable optical elements with two axes of rotation
Publication number: 20060028094Abstract: In one embodiment, a rotatable element includes a plate, a plate support, a cradle, and a cradle support. The plate is coupled to the cradle via the plate support. The cradle is coupled to a surrounding frame by the cradle support. The plate and cradle are suspended over a cavity so that, in conjunction with the plate support and the cradle support, both the plate and cradle are capable of freely rotating about different axes of rotation when suitably actuated. Since the plate is capable of rotating independently of the cradle, yet also rotates when the cradle is rotated, the plate is rotatable about two axes of rotation. In some cases, the axis of rotation of the plate is perpendicular to the axis of rotation of the cradle. Since the cradle does not surround the plate, the plates of adjacent rotatable elements can be placed very close to one another (i.e., as close as about 1 micron) to provide, for example, an array of very-closely-spaced mirrors.Type: ApplicationFiled: October 3, 2005Publication date: February 9, 2006Inventors: Dennis Greywall, Dan Marom -
Publication number: 20050225835Abstract: The specification describes an improved Moving Anti-Reflection Switch (MARS) device structure that largely eliminates charge build up on the movable membrane, and reduces stresses that cause curling of the membrane. The improved device uses a movable membrane made of single crystal silicon.Type: ApplicationFiled: February 18, 2005Publication date: October 13, 2005Inventors: David Bishop, Keith Goossen, Dennis Greywall, James Walker
-
Publication number: 20050200938Abstract: A MEMS device having a movable mirror pixel supported on a substrate and coupled to a motion actuator located between the mirror pixel and the substrate so as to enable rotation of the mirror pixel about an axis lying within the mirror plane. In one embodiment of the invention, the motion actuator has a movable electrode, on which the mirror pixel is mounted. The movable electrode is supported on the substrate by a pair of upright springs, each having two parallel segments joined at one end of the spring and disjoint at the other end. One disjoint segment end is coupled to the substrate, while the other disjoint segment end is coupled to the movable electrode. The end of the upright spring corresponding to the joined segment ends points away from the substrate such that (i) the spring body protrudes through a narrow slot in the mirror pixel and (ii) the mirror plane lies at about the mid-point of the spring.Type: ApplicationFiled: March 9, 2004Publication date: September 15, 2005Inventor: Dennis Greywall
-
Publication number: 20050189671Abstract: Carbon particles, such as, carbon fibrils and carbon nanotube molecules, may be assembled into substantially pure aligned fibers by a) dispersing the carbon particles within a curable liquid, b) aligning the carbon particles by flowing the mixture of curable liquid and carbon particles down a tapering tube, and c) curing the flowing mixture of curable liquid and carbon particles in the general vicinity of the end of the tapering tube to form a fiber. The curable liquid may be cured using ultraviolet light. The solidified mixture may be further processed by d) heating the fiber so as to cause the volatile elements of the solidified curable liquid portion to substantially dissipate from the fiber, e) twisting the fiber to increase its density, f) heating the fiber to sinter the carbon particles within the fiber, and g) cladding the fiber. The resulting fiber may then be spooled onto a take-up drum.Type: ApplicationFiled: February 27, 2004Publication date: September 1, 2005Inventors: Dennis Greywall, Bernard Yurke
-
Publication number: 20050188727Abstract: Carbon particles, such as, carbon fibrils and carbon nanotube molecules, are assembled into aligned fibers using processes derived from the processes used to manufacture optical fiber. More particularly, the carbon particles are embedded in glass, which is then drawn to align them. By aligned it is meant the axis along the longest dimension of each of the various particles in a local vicinity are substantially parallel.Type: ApplicationFiled: February 27, 2004Publication date: September 1, 2005Inventor: Dennis Greywall
-
Publication number: 20050183609Abstract: A micro-electrical-mechanical-switch (MEMS) device comprises a semiconductor wafer, a first semiconductor layer formed on the semiconductor wafer, and a second semiconductor layer formed on the first layer. A first latching movable shuttle is formed in the second layer and has the first layer removed under the first movable shuttle, the first movable shuttle being moved in a first direction relative to the wafer in response to a predetermined acceleration of the MEMS device in a direction opposite to the first direction thereby changing an operating condition of the MEMS device from a first switch state to an intermediate switch state. A second latching moveable shuttle is formed within the first shuttle, the second shuttle being moved in a second direction relative to the first shuttle in response to a thermally activated force so as to change the operating state of the MEMS device from the intermediate switch state to a second switch state.Type: ApplicationFiled: January 27, 2004Publication date: August 25, 2005Inventor: Dennis Greywall
-
Publication number: 20050174624Abstract: A MEMS device having a spring structure formed by two flexible beams attached between a substrate and a movable bar. When non-end sections of the beams are pulled in opposite directions, the beam ends attached to the movable bar pull that bar toward the substrate, thereby transforming in-plane motion of the non-end sections into out-of-plane motion of the movable bar. When the non-end sections are displaced symmetrically, the movable bar translates toward the substrate. Alternatively, when the non-end sections are displaced non-symmetrically, the movable bar rotates with respect to the substrate. In one embodiment, each flexible beam is attached to a comb-shaped portion of a motion actuator, which has two such portions, each portion interleaved with the other portion and adapted to move with respect to the substrate and that other portion.Type: ApplicationFiled: February 5, 2004Publication date: August 11, 2005Inventor: Dennis Greywall
-
Publication number: 20050156482Abstract: Two or more independent voltages are applied between stationary and movable parts of a MEMS device via a multipart spring having at least two cooperating parts that are not in direct electrical contact with each other. In one embodiment, the at least two cooperating parts include a first cooperating part and one or more other cooperating parts that are physically separated from the first cooperating part, wherein first and second independent voltages are applied via the first cooperating part and the one or more other cooperating parts, respectively.Type: ApplicationFiled: February 7, 2005Publication date: July 21, 2005Inventor: Dennis Greywall
-
Publication number: 20050134955Abstract: A MEMS device having a deformable mirror. In representative embodiments, the MEMS device includes (1) a deformable plate having a reflective surface and movably connected to a substrate and (2) a deformation actuator mounted on the plate such that, when the plate moves with respect to the substrate, the actuator moves together with the plate without any changes in the relative position of the plate and the actuator. In one embodiment, the actuator has (i) a first electrode, one end of which is attached to an edge of the plate and (ii) a second electrode attached to an interior portion of the plate. When a voltage differential is applied between the first and second electrodes, an unattached end of the first electrode moves with respect to the second electrode, thereby applying a deformation force to the plate. Advantageously, motion and deformation of the deformable plate in such MEMS device are decoupled.Type: ApplicationFiled: December 19, 2003Publication date: June 23, 2005Inventors: Dennis Greywall, Dan Marom