Abstract: There is disclosed a flat planar pressure transducer which comprises a planar insulative substrate of a rectangular configuration. Disposed on the substrate is an array of conductive areas which extend from a contact terminal area of said substrate to an end of the substrate. There is a leadless sensor module positioned at said contact terminal area, with the contacts of said leadless sensor contacting contact terminals of said contact terminal area. The leadless sensor is enclosed by an enclosure which is coupled to the substrate and surrounds the sensor. The enclosure has a screen positioned on the top surface to prevent particles from entering or damaging the leadless sensor. The above-noted structure forms a very flat, compact pressure transducer which can be utilized in lieu of flex circuit type devices and provides greater mechanical stability as well as a more accurate output.

Abstract: There is disclosed a high temperature pressure sensing system which includes a SOI Wheatstone bridge including piezoresistors. The bridge provides an output which is applied to an analog to digital converter also fabricated using SOI technology. The output of the analog to digital converter is applied to microprocessor, which microprocessor processes the data or output of the bridge to produce a digital output indicative of bridge value. The microprocessor also receives an output from another analog to digital converter indicative of the temperature of the bridge as monitored by a span resistor coupled to the bridge. The microprocessor has a separate memory coupled thereto which is also fabricated from SOI technology and which memory stores various data indicative of the microprocessor also enabling the microprocessor test and system test to be performed.

Abstract: There is disclosed a high pressure sensing header which is relatively insensitive to mounting torque. The header comprises an outer torque isolating shell which surround an inner “H” section header. The inner “H” section header has a thick diaphragm and is surrounded by the torque isolating shell which is secured to the “H” section header at a peripheral flange of the “H” section header. In this manner when the header is installed, the installation force is absorbed by the outer shell and there is no installation force or torque exhibited by the inner “H” section which will respond only to stress due to pressure. The torque isolating shell also contains a top surface which has a counterbore that accommodates a crush ring. When the unit is installed, the crush ring is crushed against an installation wall to enable the inner header to receive pressure without experiencing significant installation force.

Abstract: A filter assembly for use with a static-dynamic piezoresistive pressure transducer that measures low amplitude, dynamic pressure perturbations superimposed on top of a high static pressure through the implementation of a low-pass mechanical filter assembly is disclosed. The filter assembly may comprise a dual lumen reference tube and a removable filter subassembly further comprising a porous metal filter and narrow diameter tube. The transducer, which may be capable of operating at ultra-high temperatures and in harsh environments, may comprise of a static piezoresistive pressure sensor, which measures the large pressures on the order of 200 psi and greater, and an ultrasensitive, dynamic piezoresistive pressure sensor which may capture small, high frequency pressure oscillations on the order of a few psi or less.

Abstract: A system for sensing at least one physical characteristic associated with an engine including a turbine having a plurality of blades turning inside a casing, the system including: a pressure sensor coupled substantially adjacent to the casing and including at least one output; a port in the turbine casing for communicating a pressure indicative of a clearance between the blades and casing to the pressure sensor; a cooling cavity substantially surrounding the pressure sensor; and, an inlet for receiving fluid from the engine and feeding the fluid to the cooling cavity to cool the pressure sensor; wherein, the pressure sensor output is indicative of the clearance between the blades and casing.

Abstract: A single pressure sensing capsule has a reference pressure ported to the rear side of a silicon sensing die. The front side of the silicon sensing die receives a main pressure at another port. The silicon sensing die contains a full Wheatstone bridge on one of the surfaces and within the active area designated as the diaphragm area. Thus, the difference of the main and reference pressure results in the sensor providing an output equivalent to the differential pressure, namely the main pressure minus the reference pressure which is the stress induced in a sensing diaphragm. In any event, the reference pressure or main pressure may be derived from a pump pressure which is being monitored. The pump pressure output is subjected to a pump ripple or a sinusoidally varying pressure. In order to compensate for pump ripple, one employs a coiled tube. The tube length is selected to suppress the pump ripple as applied to the sensor die.

Abstract: An oil-filled pressure transducer including a glass pre-form having contact pins and a oil-filled tube, each running top to bottom through holes in the pre-form. The oil-filled tube extends beyond the top of the pre-form. A glass alignment plate has an alignment aperture designed to fit over the extended oil-filled tube and-another aperture placed at a predetermined position from the alignment aperture which is shaped to accommodate a sensor. When the plate is aligned over the oil-filled tube, a sensor module can be positioned accurately in the alignment aperture so that contact is made with the pins. A header having a central diaphragm is placed over the pre-form and the aligned sensor creating a space between the diaphragm and the sensor which is filled with oil. The transducer utilizes less oil and exhibits a lower backpressure with increasing temperature than other oil-filled pressure transducers of similar size.

Abstract: There is described a temperature compensation scheme for a pressure sensitive metal diaphragm transducer. The transducer employs a Wheatstone bridge fabricated from p-type piezoresistors. The Wheatstone bridge is glassed directly onto the metal diaphragm. As the temperature of operation increases, the diaphragm exhibits a temperature variation of the Modulus of Elasticity. The Modulus of the metal diaphragm decreases with increasing temperature. Because of this, the same pressure applied to the metal diaphragm causes it to deflect further, which in turns causes increased strain applied to the bridge. Because of this effect, the sensitivity of the transducer increases with increasing temperature. A resistor is now placed in series with the Wheatstone bridge. The resistor is in series with the biasing voltage and because the TCS of the diaphragm is of an opposite sign, the series resistor has an even higher TCR in series with the bridge.

Abstract: A sensor array for a pressure transducer having a diaphragm with an active region, and capable of deflecting when a force is applied to the diaphragm. The sensor array disposed on a single substrate, the substrate secured to the diaphragm. The sensor array having a first outer sensor near an edge of the diaphragm at a first location and on the active region, a second outer sensor near an edge of the diaphragm at a second location and on the active region, and at least one center sensor substantially overlying a center of the diaphragm. The sensors connected in a bridge array to provide an output voltage proportional to the force applied to the diaphragm. The sensors dielectrically isolated from the substrate.

Abstract: A semiconductor filter is provided to operate in conjunction with a differential pressure transducer. The filter receives a high and very low frequency static pressure attendant with a high frequency low dynamic pressure at one end, the filter operates to filter said high frequency dynamic pressure to provide only the static pressure at the other filter end. A differential transducer receives both dynamic and static pressure at one input port and receives said filtered static pressure at the other port where said transducer provides an output solely indicative of dynamic pressure. The filter in one embodiment has a series of etched channels directed from an input end to an output end. The channels are etched pores of extremely small diameter and operate to attenuate or filter the dynamic pressure.

Abstract: A pressure sensor including: a deflectable diaphragm including a substantially central boss and channel; and, an optical waveguide having first and second arms, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel.

Abstract: There is disclosed flat planar pressure transducer which comprises a planar insulative substrate of a rectangular configuration. Disposed on the substrate is an array of conductive areas which extend from a contact terminal area of said substrate to an end of the substrate. There is a leadless sensor module positioned at said contact terminal area, with the contacts of said leadless sensor contacting contact terminals of said contact terminal area. The leadless sensor is enclosed by an enclosure which is coupled to the substrate and surrounds the sensor. The enclosure has a screen positioned on the top surface to prevent particles from entering or damaging the leadless sensor. The above-noted structure forms a very flat, compact pressure transducer which can be utilized in lieu of flex circuit type devices and provides greater mechanical stability as well as a more accurate output.

Abstract: There is disclosed a high pressure sensing header which is relatively insensitive to mounting torque. Essentially the header consists of an outer torque isolating shell which has a “C” shaped cross section with the cylindrical shell surrounding an inner “H” section header. The inner “H” section header has a thick diaphragm and is surrounded by the torque isolating shell which is secured to the “H” section header at a peripheral flange of the “H” section header. In this manner when the header is installed, the installation force is absorbed by the outer shell and there is no installation force or torque exhibited by the inner “H” section which will respond only to stress due to pressure. The torque isolating shell also contains a top surface which has a counterbore which can accommodate a crush ring, and when the unit is installed, the crush ring is forced or crushed against an installation wall to enable the inner header to receive pressure without experiencing any significant installation force.

Abstract: There is disclosed a method and apparatus for mounting a leadless semiconductor chip on a header. The semiconductor chip has contacts on a surface and the chip is of a specified geometric shape. The header has a contact surface for receiving the chip with the contact surface of the header containing header contact pins, which pins have to contact the contacts on the semiconductor chip. The header has a guide pin extending from the contact surface and there is a guide plate which has an aperture adapted to be placed over the guide pin, the guide plate further has a chip accommodating aperture of the same geometric shape as the chip. The guide plate, when placed over the guide pin enables the chip to be placed in the chip accommodating aperture so that the contacts of the header pin are properly and accurately aligned with respect to the contacts on the semiconductor chip.

Abstract: There is disclosed a redundant pressure sensing chip which includes first and second redundant devices. Each pressure sensing device produces an output proportional to applied pressure irrespective of vibration/acceleration of the device. Each device also provides an output proportional to pressure and because of the nature of the devices, thermal effects as well as acceleration and the vibration are canceled. Based on chip operation and subtracting the signals from the two diaphragms, acceleration/vibration is canceled but also the effects of absolute pressure and differential pressure is also canceled. Therefore the chip can be used as a redundant absolute pressure sensor as well as a differential pressure sensor.

Abstract: A pressure transducer has an H-shaped cross-sectional header having a front and a back section. The front and back sections are of equal diameter and are circular. Each front and back section has a depression with an isolation diaphragm covering the depression. Each diaphragm is of equal size and the depressions communicate one with the other via a central channel in the central arm of the H. A pressure sensor communicates with the channel, where the pressure sensor responds to a first pressure applied to the first isolation diaphragm and a second pressure applied to the second isolation diaphragm. The pressure sensor produces an output equal to the difference in pressure. The differential pressure transducer having both diaphragms of the same size and still enabling leads from the sensor to be brought out.

Abstract: There is disclosed a high temperature pressure sensing system which includes a SOI Wheatstone bridge including piezoresistors. The bridge provides an output which is applied to an analog to digital converter also fabricated using SOI technology. The output of the analog to digital converter is applied to microprocessor, which microprocessor processes the data or output of the bridge to produce a digital output indicative of bridge value. The microprocessor also receives an output from another analog to digital converter indicative of the temperature of the bridge as monitored by a span resistor coupled to the bridge. The microprocessor has a separate memory coupled thereto which is also fabricated from SOI technology and which memory stores various data indicative of the microprocessor also enabling the microprocessor test and system test to be performed.

Abstract: It is an object of the present invention to provide a pressure transducer having a header wherein the header is comprised of a first section and a second section that are offset from each other. Each first and second section has a flexible diaphragm adapted to receive a first and second pressure, respectively. A central channel connects the diaphragms and a pressure sensor, located within the central channel, communicates with the channel and produces an output equal to the difference between the first and second pressures. The resultant device is a low differential pressure transducer which enables one to bring leads from the sensor out while having diaphragms of substantially the same size and diameter, therefore enabling the diaphragms to exhibit the same back pressure and be equally compliant.

Abstract: A wireless interface system can interface with any one of a plurality of transducers of different types, such as pressure sensors, temperature sensors, current probes and so on. In the system, all such transducers employ identical connectors with a common connecting scheme. In this manner, any transducer can be connected to a wireless interface which has the same input connection scheme. When the wireless interface is connected to the transducer, a rechargeable battery, which is associated with the wireless interface, is activated. The wireless interface then determines the type of transducer being utilized and provides sufficient circuitry as well as determining the requirements of the connected transducer.

Abstract: It is an objective of the present invention to provide a highly sensitive optical pressure sensor that uses a Mach-Zehnder Interferometer to measure pressure. The pressure sensor comprises a deflectable diaphragm including a substantially central boss and channel and an optical waveguide having a first arm and a second arm, wherein the first arm is substantially aligned with an edge of the boss and the second arm is substantially aligned with an edge of the channel, and further wherein the first and second arms contain a periodic array of etched holes to improve the overall sensitivity of the pressure sensor. The pressure sensor further comprises a light source coupled to the optical waveguide for introducing light to the waveguide and a light detector coupled to the waveguide for detecting changes in the intensity of light. The change in light intensity is then correlated to an applied pressure.