Kulite Semiconductor Products, Inc.

Joseph R Van DeWeert

Anthony D Kurtz

Boaz Kochman

Alexander A Ned

A system for measuring a multiplicity of pressures as those experienced by a model in a wind tunnel is depicted. The system includes individual sensor devices which are connected to an Acquisition and Compensation electronics module. The individual sensor or transducer devices are semiconductor piezoresistive devices and are connected to the Acquisition and Compensation electronics module by means of a cable in a first embodiment. In an alternate embodiment the system uses connectors which connect each of the individual sensor devices to the Acquisition and Compensation electronics module via a mating connector located therein. The connectors may also include a memory which stores compensation coefficients associated with each of the various sensor devices. In this manner as described, the transducers which are small devices are connected via electrical lines or cables to the central Acquisition and Compensation electronics modules. This module houses electronics which digitally converts the data from the sensors and then compensates the data for temperature effects. The advantage of the system is that each individual sensor does not have any compensation and it can be made very small to operate at very high temperatures without any loss of accuracy. Thus, a large number of sensors can be utilized in a very small volume, even under extreme environmental conditions. It is noted that the Acquisition and Compensation electronics module can be located remotely in a safe environment outside of the wind tunnel and therefore respond extremely accurately to the pressure and temperatures subjected by the model in the wind tunnel.

High temperature, high bandwidth pressure acquisition system

There is disclosed a mounting technique for mounting a semiconductor chip of the leadless or so-called flip chip type to a header. The header has an insert made of glass or other suitable non-conductive material within the header hollow. Mounted into the glass insert are a series of conductive metal pins which are placed in areas so that when a chip is mounted in the header, the chip makes contact with these conductive pins and allows one to make outside connections. Also positioned in the header are a series of nonconductive guide pins. These pins are placed in suitable positions in the header to enable one to contact the outside surfaces of the chip when the chip is placed in the header. In this manner, the chip is constrained from movement from side to side or from rotation. However, due to the positioning of the nonconductive pins within the header, it is possible to move the chip up and down while mounting.

Leadless alignment of a semiconductor chip

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. In this manner, the bridge voltage is made to decrease with increasing temperature. Due to the fact that the bridge voltage decreases with increasing temperature the change in voltage compensates for the change in the Modulus of the metal diaphragm and therefore provides an accurate output at all temperatures.

Method for temperature compensation of a piezoresistive gaged metal diaphragm

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.

Micromachined optical pressure sensor

A pressure sensing apparatus including: at least one deflectable diaphragm having a center, wherein each diaphragm supports: at least one positive piezoresistive gauge and at least one negative piezoresistive gauge coupled in series across a voltage differential in a half-Wheatstone bridge configuration having an output between the positive and negative piezoresistive gauges; and, a compensating piezoresistive gauge coupled in series with the half-Wheatstone bridge configuration across the voltage differential; wherein, the compensating piezoresistive gauge is nearer the center of the diaphragm than the negative piezoresitive gauge, the negative piezoresitive gauge is nearer the center of the diaphragm than the positive piezoresitive gauge, and the compensating piezoresistive gauge linearizes the half-Wheatstone bridge output.

Apparatus and methods for linearizing piezoresistive wheatstone bridges

A method and apparatus for measuring knocking in internal combustion engines employs a high temperature transducer, which transducer is mounted within a cylinder. The output of the transducer is solely related to pressure. The output signal from the transducer is directed to the input of a high frequency amplifier associated with a band pass filter. In this manner the combustion signal can be filtered out and one provides a signal which is only indicative of the knocking signal and of the knocking frequencies. This signal can be analyzed simply and effectively by the use of a processor such as a multimeter or a microprocessor. In a similar manner the processor can compare the combustion and knocking signal without the band pass filtering with the knocking signal with the combustion signal filtered out.

Method and apparatus for measuring knocking in internal combustion engines

A thin layer of ionic crystal is grown on a substrate. The crystal could be any type of ionic crystal, such as sodium chloride or potassium chloride. The crystal is a pure form of the chosen compound and may contain contaminants which would shift the wavelength of created color centers. On top of the first crystal layer, a second thin layer of a different type of crystal is deposited, such as lithium fluoride or sodium fluoride. When these two layers are radiated with gamma rays, they will each form color centers at the spots radiated. Because of the difference in crystalline properties of the two different ionic crystal centers, their color centers would be at different wavelengths. Each of the two separate ionic crystals will emit light at different characteristic wavelengths when illuminated at their unique absorption frequencies. Each layer can be made to lase separately. The top layer has an absorption energy greater than that of the bottom layer, so that the layer energy of the bottom layer absorption peak will pass through the top layer and be absorbed only by the bottom layer. There are many ways of forming F-centers in the two superimposed layers, such as by the use of selective gamma radiation by heating of an anion layer of the particular compound and then depositing the second ionic crystal on the first ionic crystal and then depositing an anion layer on the second crystal and then heating to produce a structure which will lase it to the different frequencies.

Dual layer color-center patterned light source

The present invention relates to a compensated pressure transducer having a pressure transducer connected to a coarse temperature adjustment compensator and to a fine temperature adjustment compensator. The coarse temperature adjustment compensator includes an analog circuit and the fine temperature adjustment compensator includes a digital circuit. A pre-amplifier is connected between the pressure transducer and the fine temperature adjustment compensator.

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Cliffside Park, NJ, United States of America

Joseph R Van DeWeert