Abstract: A silicon capacitive microsensor which is sensitive to acceleration forces includes a silicon capacitive sensing element 10 comprising three silicon layers 12,16,26 having glass dielectric layers 14,24 between each pair of silicon layers with the middle silicon layer 16 consisting of a proof mass 18 suspended between the two glass dielectric layers 14,24 by a silicon hinge 20 which is connected to a slightly thicker silicon support layer 17 around the periphery (FIG. 3 ) between the glass layers 14,24 (FIG. 1 ). Three metallic bond pads 40,42,44 on the surface 45 of the silicon layers 26,16,12, respectively, are soldered to circuit trace pads 108 on a circuit board 100 which has a glass upper layer 104 and a silicon support layer 102. The thermal expansion coefficient between the glass layer 104 and the sensing element 10 are substantially the same, thereby minimizing thermally induced stresses on the sensing element 10 and minimizing inaccuracies associated therewith.

Abstract: A silicon capacitive pressure sensor is disclosed that has a glass dielectric material sputter-deposited onto a silicon substrate of the sensor. After deposition of the bulk dielectric material, the glass is patterned and etched to form a pair of concentric rings. An inner ring is of a circular shape, while the outer ring is of an octagonal shape. As compared to prior art dielectric spacers which are of a single ring of relatively wide thickness, the pair of concentric rings disclosed herein significantly reduce the parasitic capacitance of the glass dielectric material, thereby increasing the sensitivity of the sensor.

Abstract: A dual-element, parallel-plate silicon capacitative pressure sensor includes a pressure sensing element and a reference element of identical structure. Both elements are separately fabricated from the same silicon wafers using identical processing steps. Further, both elements are simultaneously mounted to a header using identical mounting steps. Such identical fabrication and mounting steps serve to identically match the dielectric materials and, thus, the aging properties of both the sensing and reference elements. By matching the sensing and reference elements in these ways, and by aging these components at elevated temperatures in exactly the same way, it is possible to achieve an extremely close match in long-term dielectric aging properties.

Abstract: A dual-element, parallel-plate silicon capacitative pressure sensor includes a pressure sensing element and a reference element of identical structure. Both elements are fabricated from the same silicon wafers using identical processing steps. Further, both elements are simultaneously mounted to a header using identical mounting steps. Such identical fabrication and mounting steps serve to identically match the dielectric materials and, thus, the aging properties of both the sensing and reference elements. By matching the sensing and reference elements in these ways, and by aging these components at elevated temperatures in exactly the same way, it is possible to achieve an extremely close match in long-term dielectric aging properties.

Abstract: An obstruction detection system includes emitters, a sensor, and obstruction detection circuitry. The emitters mounted along the top of an opening radiate a plane of light toward the floor. The plane of light intersects the floor and creates a floorline at the intersection of the plane of light and the floor. The plane of light also intersects the door edge and creates a door edge line at the intersection of the door edge and the plane of light. A sensor, located outside the plane of light, monitors the opening so that the presence of the obstruction can be detected from a change in a received light pattern of the floorline, the door edge line, and from reflections from an obstruction in the plane of light. The sensor provides an output signal in response to the received light pattern to a means for analyzing said sensor output signal for obstruction detection.

Abstract: A silicon capacitive pressure sensor is disclosed having a silicon substrate and a silicon diaphragm separated by a glass dielectric spacer. The substrate has an upper surface formed as a mesa which is generally curved in shape, the curvature being concave. Due to manufacturing constraints the mesa upper surface comprises a series of concentric rings that approximate the desired concave shape. The step height and diameter of the rings are such that, at full deflection of the diaphragm, the diaphragm touches the center of the mesa, but not the edges of the individual steps. That is, letting the edges or corners of the steps define a curve, the radius of curvature of the diaphragm is smaller than the radius of curvature of the locus of the step corners.

Abstract: Pressure sensors utilizing capacitance variations to sense pressure variations of the silicon-on-silicon type in which dielectric drift, which occurs in such sensors due to the changing characteristics primarily of the dielectric wall support layer (16) extending up from the silicon substrate (12) between it and the silicon diaphragm (11), is minimized by in turn minimizing the contribution of the dielectric layer to the total capacitance of the sensor (10), reducing the dielectric contribution of the capacitance from, for example, about fifty (50%) percent down to a range of no more than about twenty to twenty-five (20-25%) percent and down typically to sixteen to about ten (16%-10%) percent of the total capacitance or lower. Three exemplary approaches are illustrated, namely, etching the outer edges of the dielectric layer, making the wall(s) it form(s) thinner (FIG.

Abstract: A micromachined three-plate capacitive accelerometer incorporates hinges attached to top and bottom surfaces of the proof mass that are symmetric about X and Y axes and also about diagonal axes; passageways for gas film damping in the fixed members that do not affect the capacitance to any significant degree; and provision for independently selecting two of the parameters sensitivity, capacitance and maximum acceleration.

Abstract: A micromachined three-plate capacitive accelerometer incorporates hinges attached to top and bottom surfaces of the proof mass that are symmetric about X and Y axes and also about diagonal axes; passageways for gas film damping in the fixed members that do not affect the capacitance to any significant degree; and provision for independently selecting two of the parameters sensitivity, capacitance and maximum acceleration.

Abstract: A micromachined three-plate capacitive accelerometer incorporates hinges attached to top and bottom surfaces of the proof mass that are symmetric about X and Y axes and also about diagonal axes; passageways for gas film damping in the fixed members that do not affect the capacitance to any significant degree; and provision for independently selecting two of the parameters sensitivity, capacitance and maximum acceleration.

Abstract: The present invention is related to a sight glass(10) that utilizes both reflected light at a glass to air interface(40) as well as the light transmitted through a glass to fluid to glass interface(44) to form a light pattern that is indicative of the true fluid level. By requiring that light always appear in either an "air" or "fluid" channel(42,46), any absence of light is assumed due to film coated surfaces or to other abnormal conditions. An absence of light is a signal that maintenance is required.

Abstract: The method and apparatus for generating start of combustion signals associated with the combustion events in a diesel engine (10), and for using such signals to control the timing of fuel delivery to the engine. The combustion event is sensed, as by an electrostatic (230, 330) or optical (130, 430) sensor, and signal conditioning circuitry (32) provides a start-of-combustion (SOC) signal (34) which is directly and precisely indicative of the time of the onset of combustion. The sensors (130, 230) include self-cleaning capabilities (48, 248) for extended operating life on an engine. The sensors may be incorporated in the structure of a glow plug (330, 430). The SOC signal (34) is advantageously supplied to a timing control circuit (26) which delivers a timing control signal (28) to a fuel delivery device, such as the controller (16') associated with a fuel pump (16).

Abstract: A display device employs an electric discharge passing through a mixture of gases to form an excimer that fluoresces in the blue/green region of the optical spectrum.

Abstract: The method and apparatus for generating start of combustion signals associated with the combustion events in a diesel engine, and for using such signals to control the timing of fuel delivery to the engine. The combustion event is sensed, as by an electrostatic or optical sensor, and signal conditioning circuitry provides a start-of-combustion signal which is directly and precisely indicative of the time of the onset of combustion. The sensors include self-cleaning capabilities for extended operating life on an engine. The sensors may be incorporated in the structure of a glow plug.The SOC signal is advantageously supplied to a timing control circuit which delivers a timing control signal to a fuel delivery device, such as the controller associated with a fuel pump. The control circuit stores one or more start of combustion values which indicate the desired timing, relative to an engine cycle, for the start of the combustion event as a function of speed and load.

Abstract: A flowmeter for the measurement of fluid flow employs a combination of two transit times for the passage of charged particles through a known distance under different conditions. Applications include the measurement of the air-fuel mixture in automobile engines.

Abstract: Various apparatus and their applications to the determination of the flux of a fluid flowing through a region in accordance with the present invention are disclosed. The technique involved is based on the formation of charged particles within the fluid and subjecting these particles to an electric field which is colinear with the direction of fluid travel. Two charged particle collection stations are established, one upstream and the other downstream of the charged particle formation site and the resulting electric currents through such stations are correlated to the flux of the fluid.

Abstract: Apparatus for providing ions having a specific electric charge to a stream of working fluid are disclosed. The ions are produced by a variety of techniques in a volume of the working fluid which is maintained in a protected region within the stream. An electric field draws ions away from the production region and makes them available to the stream of fluid. In many applications an independent electric field is applied to the flowing fluid to move the ions within the working fluid.

Abstract: A sensor for measuring the flux of a gas and some simple alternate embodiments are disclosed. The sensor employs charged particle techniques and includes provision for compensating for environmentally produced changes in the charged particle source. The basic device includes an active region containing the charged particle source located between two upstream charged particle collectors and two downstream charged particle collectors, means for maintaining suitable electric fields between the charged particle source and the collectors, and means for measuring the electric current flowing in each collector. In operation, the sensor is able to compensate for changes in the charged particle source characteristics which would otherwise result in a change of sensor calibration.

Abstract: Electric discharge method and apparatus for producing a relatively large volume, diffuse glow gas discharge plasma for laser, chemical synthesis and other applications at high power, high pressure and high volume levels and such that plasma properties are dominated by collision processes and wherein the operational parameters of the electric discharge are established to provide an average gas residence time T.sub.R in a continuous wave convective electric discharge and a discharge duration time T.sub.P in a pulsed electric discharge that is approximately equal to the plasma instability growth time T.sub.G = CP/JE where P is the pressure in Torr, JE is the electric power density in Watts/cm.sup.3 and C is a constant typically about 10.sup.-.sup.4 for self-sustained gas electric discharges and 10.sup.-.sup.

Abstract: New and improved ion collection means for use in flow meter apparatus which utilizes the migration of ions transverse to the direction of flow of a moving fluid to determine flow characteristics are disclosed. The ion collector comprises individual strips of electrically conductive material arranged in an orderly manner at the collection site. The strips are physically separate and connected in electrical series with each other through suitable resistors which are protected from the flow of moving fluid.