Simon Fraser University

Other

Memsic, Inc.

Acemore International Ltd.

Albert M Leung

Yang Zhao

Yongyao Cai

Alexander Dribinsky

Michael E Rebeschini

Gregory P Pucci

Adrian P Brokaw

Leyue Jiang

Yaping Hua

Meenakshinathan Parameswaran

See-Ho Tsang

Angular rate sensors cause a stream of fluid to flow by heating the fluid. A trajectory of the stream of fluid is deflected by Coriolis forces. Apparatus according to some embodiments provides two heaters spaced apart along a channel. A stream of gas can be made to flow along the channel by operating one of the heaters. The flow can be periodically reversed by alternating operation of the heaters. Temperature sensors may be applied to detect deflection of the flowing gas. Angular rate sensors may be fabricated inexpensively by micromachining techniques.

Rotation sensing apparatus and methods

Microstructures can be formed as patterned layers on a substrate and then erecting the microstructures out of the plane of the substrate. The microstructures may be formed over circuits in the substrate. In some embodiments the patterned layer provides resiliently-flexible members such as cantilevers or springs that can be buckled to permit an edge defined by the patterned layer to engage a surface of the substrate. In some embodiments deformation of the resiliently-flexible members results the edge being forced against the substrate. Such microstructures may be applied in a wide range of applications including supporting optical elements, sensors, antennas or the like out of the plane of a substrate. Examples of accelerometer structures are described.

Three-dimensional microstructures and methods for making same

Single chip 3-axis thermal accelerometer devices include a substrate, at least one cavity etched in the substrate, a fluid disposed in the cavity, a bridge structure suspended over an opening of the cavity, and a plurality of heater elements and temperature sensing elements disposed on the bridge structure. The substrate has a substantially planar surface defined by X and Y coordinate axes, and the bridge structure is suspended over the opening of the cavity in the X-Y plane. In one embodiment, the bridge structure is configured to position at least two of the temperature sensing elements out of the X-Y plane. The heater and temperature sensing elements are disposed on the bridge structure in optimized arrangements for providing reduced temperature coefficients and for producing output voltages having reduced DC offset and drift.

Single chip tri-axis accelerometer

A thermal accelerometer device that provides a compensation for sensitivity variations over temperature. The thermal accelerometer includes signal conditioning circuitry operative to receive analog signals representing a differential temperature is indicative of a sensed acceleration. The signal conditioning circuitry includes serially connected A-to-D and D-to-A converters, which implement a temperature dependent function and process the received signals to provide a compensation for sensitivity variations over a range of ambient temperature. To provide a ratiometric compensation for variations in power supply voltage, a buffered voltage proportional to the supply voltage is provided as a reference voltage to the D-to-A converter. The thermal accelerometer includes a self-test circuit for verifying the integrity of a heater, temperature sensors, and circuitry included within the device.

Method and circuitry for thermal accelerometer signal conditioning

A thermal pressure sensor monitors pressure by measuring effects caused by variations of thermal conductivity between a member and a substrate to which the member is adhered by stiction. The interface between the member and the substrate behaves as an extremely narrow gap. In a preferred embodiment the member is a bridge extending between a pair of cantilever arms. Two pressure sensors may be combined in a Wheatstone bridge configuration. A method for fabricating a pressure sensor according to the invention comprises forming a layer of oxide on a substrate, depositing a layer of material on the oxide layer, forming the member from the layer of material, removing the oxide layer and then bringing the member into contact with the substrate. The portion of the substrate under the member may be patterned with plateaus and valleys.

Gas pressure sensor based on short-distance heat conduction and method for fabricating same

An integrated convective accelerometer device. The device includes a thermal acceleration sensor having a thermopile and a heater element; control circuitry for providing closed-loop control of the thermopile common-mode voltage; an instrumentation amplifier; clock generation circuitry; voltage reference circuitry; a temperature sensor; and, output amplifiers. The device can be operated in an absolute or ratiometric mode. Further, the device is formed in a silicon substrate using standard semiconductor processes and is packaged in a standard integrated circuit package.

Thermal convection accelerometer with closed-loop heater control

An accelerometer has a substrate with a cavity therein, a heater extending over the cavity, and a pair of temperature sensitive elements each spaced apart from the heater a distance of 75-400 microns also extending over the cavity. On passing an electrical current through the heater a symmetrical temperature distribution is set up on both sides of the heater. On acceleration, this distribution moves and by measuring the temperature as sensed by the pair of temperature sensitive elements the acceleration that caused the shift can be calculated.

Accelerometer without proof mass

A process for fabricating an accelerometer, which includes providing a substrate with a layer of electrically conductive material on the substrate, micromachining the substrate to form a central electrical heater, a pair of temperature sensitive elements, and a cavity beneath the heater and the temperature sensing elements. Each temperature sensing element is spaced apart from said heater a distance in the range of 75 to 400 microns. The temperature sensing elements are located on opposite sides of the heater, thereby forming an accelerometer.

An accelerometer having a substrate with a cavity therein, a heater extending over the cavity, a pair of temperature sensitive elements extending over the cavity equidistant from the heater, and an electrical conductor couplable to an external power source and operative to pass electrical current through the heater so as to develop a symmetrical temperature gradient in the fluid extending outwardly from the heater to the two temperature sensors. The fluid may be a liquid or a gas surrounding the heater and temperature sensors. Applied acceleration disturbs this symmetry and produces a differential temperature between the two temperature sensors proportional to the acceleration.

A laser, direct-write system for making personalized custom or semi-custom integrated circuits with a very fast turnaround time. The system includes a method and apparatus for high percision scanning of a submicron laser spot. The laser beam is scanned at the entrance of a beam expander. The beam expander reduces the scan angle and error produced by a mechanical scanning device such as a rotating polygonal mirror. The smaller scan angle at the output of the beam expander matches well with the projection optics of a laser, direct-write semi-custom integrated circuit production system. The scan error reduction permits more accurate positioning of the focussed laser spot on the surface of the semi-custom integrated circuit.

Laser, direct-write integrated circuit production system

Joystick controller apparatus in which a pair of joystick controllers may send signal bursts on the same communication channel in the infrared frequency range by means of an electromagnetic transmission without recognizable loss of data. An error checking system is also provided to eliminate the effects of noise. A universal cable connector is provided for connection to various video game apparatus.

Growing community of inventors

Burnaby, Canada

Albert M Leung