Abstract: A microactuator of a silicon substrate having a frame with a central circular flexible diaphragm suspended from the substrate by a hinge. The hinge is a layer of silicon dioxide of uniform thickness which is formed by etching a groove in the silicon substrate and then conformally forming a silicon dioxide layer of uniform thickness in the groove. The substrate backside is then etched to the desired diaphragm thickness, exposing the bottom portion of the silicon dioxide layer which thereby becomes the hinge. Further a split hinge structure includes two such hinges which are parallel in part and so overlap in length, with a silicon bridge portion of the diaphragm lying therebetween. The electrical traces which extend from the frame to the central portion of the diaphragm are deposited on the silicon bridge, minimizing the mechanical stress on the traces due to hinge flexing.

Abstract: The invention features a melt pressure measurement device for measuring the pressure of a melted substance useful in cooled state for forming solid objects. The device comprises a probe for insertion through an aperture in a wall of a melt-containing vessel, with the probe having a pressure-deflectable end surface for contact with pressurized melt. The probe has pressure-resistant securing means for fixing the probe in the wall with the end surface of the probe exposed for contact with the melt in a non-flow obstructive relationship. A seal surface on the probe between the end of the probe and the securing means provides cooperative sealing action with a mating sealing means associated with the wall to prevent exposure of the melt to the securing means. The probe also has pressure detection means internal of the probe, responsive to deflection of the end surface of the probe, for detecting pressure of the melt.

Abstract: A transducer having a plurality of sensing elements disposed in a single diaphragm wherein each of the sensing elements is spaced from every other of the sensing elements a predetermined distance so as to control interference among the sensing elements. Each of the sensing elements preferably comprises a plurality of piezoresistors each of which are coupled in a Wheatstone bridge configuration. This transducer achieves sensitive, accurate, high spatial resolution measurements of non-uniform pressures.

Abstract: A non-dispersive infrared gas analyzer especially adapted for measuring the concentrations of HC, CO and CO.sub.2 in a vehicle exhaust includes a sample chamber for holding a sample gas, a radiation emitter for directing a beam through the chamber and a detector for indicating the amount of radiation absorbed. A plurality of filters each of which transmit radiation at an absorption band of a gas component to be detected are alternatingly positioned in the radiation path to produce a time-multiplexed signal having concentration information for all gases. The time-multiplexed detector output is corrected for gain and offset errors "on-the-fly", without requiring demultiplexing, through the use of an analog multiplier circuit. The correction factors are themselves determined without demultiplexing the detector output signal.

Abstract: An improved diaphragm sensor employs silicon-on-silicon technology and has monolithic integrated signal conditioning circuitry. The support circuitry minimizes the effects of stray capacitance and may be configured to provide either analog or digital output to external terminals. It has a wide band of linearity and is particularly useful for accurately measuring pressures less than 0.5 PSI. The sensor is constructed by joining a silicon top plate having a mechanical pressure stop, a reduced thickness silicon diaphragm and a back plate having CMOS circuitry thereon. These components are bonded together by eutectic soldering.

Abstract: A semiconductor transducer or actuator is disclosed. The transducer and actuator each include a deflecting member with corrugations producing increased vertical travel which is a linear function of applied force. An accurate and easily controlled method that is insensitive to front-to-back alignment is also disclosed for forming uniform corrugations of precise thickness; independent of the thickness of the deflecting member. The cross-sectional shape of the corrugations is not limited by the etching technique, so that any configuration thereof is enabled.

Abstract: A thermostatic switch has a contact arm which is adapted for reducing contact pressure and maximizing wiping action between fixed and movable contacts. The switch includes a housing, a pair of terminals mounted in the housing, a resilient contact arm connected to one of the terminals, a movable contact on the contact arm, a stationary contact connected to the other terminal, and an actuator assembly for opening and closing the switch. The contact arm is integrally struck from a resilient, electrically conductive metal and it includes a base portion, and a pair of supporting members extending outwardly and upwardly from the base portion and then bending back thereover merging into a main portion. The main portion includes a peripheral edge portion having a contact area, and a plurality of finger portions which converge inwardly therefrom and merge into an actuator portion.

Abstract: A thermocouple connector for measuring the temperature of a surface includes a heat conductive casing having a hollow interior and a linear ridge on one side. The apex of the linear ridge forms a contact zone with the surface. A pair of thermocouple leads extends into the hollow interior of the casing, and are attached to the casing at and parallel to the linear ridge. The contact zone is sufficiently wide in relation to the distance of the contact zone from the leads such that welds along the side of the contact zone penetrate the contact zone, but do not penetrate so far as to burn the leads.

Abstract: A semiconductor transducer or acutator is disclosed. The transducer and actuator each include a deflecting member with corrugations producing increased vertical travel which is a linear function of applied force. An accurate and easily controlled method that is insensitive to front-to-back alignment is also disclosed for forming uniform corrugations of precise thickness; independent of the thickness of the deflecting member. The cross-sectional shape of the corrugations is not limited by the etching technique, so that any configuation thereof is enabled.

Abstract: An apparatus and method of operation for a self-testable accelerometer having a housing, a diaphragm for detecting movement in response to an applied force, a mass on the diaphragm, at least one capacitive plate attached to the housing and disposed such that a potential difference between the capacitive plate and the mass causes a movement of the mass, electrodes for applying a potential difference between the mass and the capacitive plate, and at least one piezoresistive element attached to the housing and the diaphragm for sensing movement of the mass. The accelerometer's housing comprises a frame, a base and a cap with air gaps providing squeeze film damping and mechanical stops for inhibiting movements of the mass. The combination of the capability to electrostatically produce a movement of the mass and the piezoresistive sensing of that movement allows testing and calibration of the accelerometer at any stage in its manufacture or deployment without the need for external equipment such as shakers.

Abstract: A method and apparatus for measuring the concentration of one or more emission gases in the exhaust of a vehicle, including a conventional gas analyzer and a transducer for monitoring at least one parameter directly related to the operating condition of the vehicle. Samples of gas emissions are supplied to the gas analyzer and the transducer is monitored while the vehicle is operated in a convention manner. A running history of readings of exhaust gas concentration(s) of interest is maintained during vehicle operation with earlier readings being supplanted by recent ones. Upon the occurrence of a predetermined event, the running history is preserved in order to provide a correlation between the exhaust gas concentrations and known operating parameters of the vehicle.

Abstract: A semiconductor microactuator has a silicon semiconductor substrate having suspension means connected thereto. The suspension means has a first layer of material having a first thermal expansion coefficient and a second layer of material having a second thermal expansion different than the first thermal expansion coefficient and may be a part of a diaphragm or a pair of connecting members. A movable element, which may be a second part of the diaphragm or a boss, is connected to the suspension to be displaced thereby as the temperature of the first and second layers of material is varied. The displacement is solely irrotational with respect to the semiconductor substrate.

Abstract: A semiconductor transducer or actuator is disclosed. The transducer and actuator each include a deflecting member with corrugations producing increased vertical travel which is a linear function of applied force. An accurate and easily controlled method that is insensitive to front-to-back alignment is also disclosed for forming uniform corrugations of precise thickness; independent of the thickness of the deflecting member. The cross-sectional shape of the corregations is not limited by the etching technique, so that any configuration thereof is enabled.

Abstract: A non-dispersive infrared gas analyzer especially adapted for measuring the concentrations of HC, CO and CO.sub.2 in a vehicle exhaust includes a sample chamber for holding a sample gas, a radiation emitter for directing a beam through the chamber and a detector for indicating the amount of radiation absorbed. A plurality of filters, each of which transmit radiation at an absorption band of a gas component to be detected, are alternatingly positioned in the radiation path to produce a time-multiplexed signal having concentration information for all gases. A calibration assembly is provided which includes a plurality of calibration cells selectively positionable in the radiation path in order to provide an internal calibration standard for two-point calibration of each gas channel. The cells contain one or more of the gas components to be measured at concentrations and pressures predetermined to compensate for the difference in optical path length between the calibration cells and the sample chamber.

Abstract: A transducer having a plurality of sensing elements disposed in a single diaphragm wherein each of the sensing elements is spaced from every other of the sensing elements a predetermined distance so as to control interference among the sensing elements. Each of the sensing elements preferably comprises a plurality of piezoresistors each of which are coupled in a Wheatstone bridge configuration. This transducer achieves sensitive, accurate, high spatial resolution measurements of non-uniform pressures.

Abstract: A system for monitoring the continuity and potential rate of leakage of an underground tank hole liner formed of a sheet of electrically insulating polymeric material in which a standard current measurement is made of a circuit comprising a standard electrode in the form of a container of electrically insulating material having a small hole in a side thereof and containing an electrically conductive fluid connected to an injection electrode through a current source, the electrodes being immersed in a conductive fluid in the bottom of the tank hole to provide a calibrated liner leakage value, and such measurement is compared with the current provided by a circuit comprising the injection electrode connected to a ground electrode through the current source.

Abstract: A contrast enhancing, substantially transparent touch panel device comprises a static element, a dynamic element and a microweave screen of a fine mesh of fine dark-colored filaments embedded within a clear adhesive layer and incorporated as an integral part of the dynamic element of the panel. Preferably there is no air gap between the front of the device and the conductive surface of the dynamic element. The device can comprise at least one layer of transparent colored coating for light attentuation, color-selective light filtering, and tint correction.

Abstract: A disc assembly for a bimetallic disc-actuated thermostatic switch is adapted to minimize response time. The switch includes a disc assembly comprising a disc retainer, and a bimetallic disc and a cap on the disc retainer. The disc retainer includes a central hub portion, a plurality of fingers which radiate outwardly from the hub portion, a plurality of disc retainer projections on the fingers adjacent the terminal ends thereof and a plurality of disc support shoulders on the fingers adjacent the disc retainer projections thereon. The fingers have open notches therebetween for reducing the cross sectional area of the material available in the disc retainer for conducting heat from the bimetallic disc to the body portion of a thermostatic switch on which the disc assembly is installed.

Abstract: A fiber optic liquid level sensor having a vertical tube which may be placed in a vessel containing the liquid to be sensed. Disposed for free movement along the exterior of the tube is an annular float equipped with a magnet. A fiber optic cable containing two optical fibers is attached to the top of the tube and the optical fibers extend to a selected point where it is desired to sense the liquid level. There the fibers terminate facing a movable mirror to which a magnet is attached. With a rising liquid level, the mirror is carried upward by the magnetic linkage of the magnet on the float and the magnet to which the mirror is attached. When the mirror reaches the focal point of the optical fibers, the light circuit is closed and an electrical signal derived therefrom may be used to open or close a switch. When the liquid level falls so that the mirror drops below the focal point of the optical fibers, the light circuit will be opened.