Abstract: A method and system of providing power to a pressure and temperature sensing element is provided. Polarity switching is added to a current source for a sensor, which includes one piezo-resistive sensing element configured as a single implant square located at an edge of a diaphragm of the element, and which produces pressure and temperature outputs. The piezo-sensing element operates as a piezo-resistive radial element when current is conducted through the element radially with respect to the diaphragm. Conversely, the piezo-sensing element operates as a piezo-resistive tangential element when current is conducted through the element tangentially to the edge of the diaphragm. A difference in the radial and tangential resistances is proportional to an applied pressure, while a sum of the resistances is a function of temperature. By alternating the polarity of power applied to the sensor, a build up of ions resulting from PUD is minimized.

Abstract: A communication device is located within a well and includes a transducer that converts a first electrical signal into a first acoustic signal for transmission through the well and that converts second acoustic signal received from the well to a second electrical signal. The transducer is at least partially coated with an anechoic material in order to reduce the effects of acoustic signal impairments, such as echoes, flow and machine noise, and reverberations. The anechoic material has a thickness that is a fraction of a wavelength of the acoustic signals.

Abstract: A microelectromechanical device and method of fabricating the same, including a layer of patterned and deposited metal or mechanical-quality, doped polysilicon inserted between the appropriate device element layers, which provides a conductive layer to prevent the microelectromechanical device's output from drifting. The conductive layer may encapsulate of the device's sensing or active elements, or may selectively cover only certain of the device's elements. Further, coupling the metal or mechanical-quality, doped polysilicon to the same voltage source as the device's substrate contact may place the conductive layer at the voltage of the substrate, which may function as a Faraday shield, attracting undesired, migrating ions from interfering with the output of the device.

Abstract: A pressure sensor has a housing with an opening exposing a cavity, a barrier diaphragm across the opening, a pressure sensing element within the cavity, and a fill fluid within the cavity. The fill fluid comprises a fluid and a filler, the fluid has a TCE associated therewith, the housing has a TCE associated therewith, and the filler lowers the TCE of the fluid to a level matching the TCE of the housing. Accordingly, the housing and the fill fluid do not exhibit temperature induced dimensional changes relative to one another that cause plastic deformation of the barrier diaphragm.

Abstract: A pressure sensor has a housing with an opening exposing a cavity, a barrier diaphragm across the opening, a pressure sensing element within the cavity, and a fill fluid within the cavity. The fill fluid comprises a fluid and a filler, the fluid has a TCE associated therewith, the housing has a TCE associated therewith, and the filler lowers the TCE of the fluid to a level matching the TCE of the housing. Accordingly, the housing and the fill fluid do not exhibit temperature induced dimensional changes relative to one another that cause plastic deformation of the barrier diaphragm.

Abstract: A communication device is located within a well and includes a transducer that converts a first electrical signal into a first acoustic signal for transmission through the well and that converts second acoustic signal received from the well to a second electrical signal. The transducer is at least partially coated with an anechoic material in order to reduce the effects of acoustic signal impairments, such as echoes, flow and machine noise, and reverberations. The anechoic material has a thickness that is a fraction of a wavelength of the acoustic signals.

Abstract: A microelectromechanical device and method of fabricating the same, including a layer of patterned and deposited metal or mechanical-quality, doped polysilicon inserted between the appropriate device element layers, which provides a conductive layer to prevent the microelectromechanical device's output from drifting. The conductive layer may encapsulate of the device's sensing or active elements, or may selectively cover only certain of the device's elements. Further, coupling the metal or mechanical-quality, doped polysilicon to the same voltage source as the device's substrate contact may place the conductive layer at the voltage of the substrate, which may function as a Faraday shield, attracting undesired, migrating ions from interfering with the output of the device.

Abstract: A transducer packaging assembly for use in a sensing unit subjected to high forces of acceleration includes a base having a cavity. A pressure sensitive semiconductor die is bonded to a large backplate having a shape so that it nestles into the cavity but is spaced from a surface of the cavity. A planar cover secured to the base has a hole larger than the die but smaller than the backplate, and thin wires extend from the die to electrical connections on the assembly. A viscous fluid fills a space between the backplate and the cavity, and a space between the backplate and the cover, and transmits a pressure to be measured to the pressure sensitive die. The viscous fluid has a sufficiently high viscosity to oppose movement of the backplate relative to the cavity while cushioning the pressure sensitive die and the backplate from forces of acceleration.

Abstract: A measurement system utilizes a sensor formed in a semiconductor on insulator structure that has an offset related to the time that power is applied. A controller applies power, obtains readings and removes power so as to minimize any effect of the offset.

Abstract: An efficient method brings together two wafers of dies that contain an infrared transparent window or top cap with either an infrared detector or emitter array to produce a low cost infrared package. A low thermal conductivity gas or a vacuum may be used between the wafers for enhanced thermal isolation. Joining of the wafers is preferably by solder, although ultrasonic bonding can be used.

Abstract: A temperature sensing device employs a resonant polysilicon beam, in combination with electrical circuitry for oscillating the beam at its natural resonant frequency, to sense changes in temperature. The resonant beam is formed as part of a silicon layer, and the silicon layer is in direct contact with a dissimilar material. In one version of the device, the silicon layer is deposited onto a sapphire substrate by low pressure chemical vapor deposition. In another version, the beam is part of a polysilicon layer deposited onto a silicon wafer substrate. The silicon substrate is thinned, then thermoelectrically bonded to a borosilicate glass substrate. In still another version, the silicon substrate is selectively thinned and has deposited thereon a TCE mismatched material. In all versions, temperature is sensed based on a thermal mismatch of the two dissimilar materials.

Abstract: An occupancy sensor having a primary infrared radiation sensor and a secondary infrared radiation sensor in an integrated vacuum package having a window that provides separate fields of view to the sensors, respectively. The primary sensor is for monitoring occupancy of a selected space. The secondary sensor is for monitoring the background radiation of the space. Signals from the primary and secondary sensors are electronically processed and compared, and the occupancy level of the selected space is determined. Temperature and visible light sensors may also be incorporated. Sensor information is used to control temperature, ventilation, lighting and other parameters of the selected space.

Abstract: A force sensing component for use with a force sensing unit includes a planar flexure member having a moveable portion separated from a fixed portion by a strain sensitive connection and a removable tab partially defined by through cuts along a crystallographic axis of the flexure member. Upper and lower stops limit movement of the beam.

Abstract: This patent relates to the fabrication of diaphragm-based microstructures used primarily for sensing physical phenomena by detecting a change in deflection, resonance, or curvature of the diaphragm. The methods of fabrication described and claimed herein relate primarily to diaphragm-based diaphragms made of silicon, either single crystal or polycrystalline in form, although other materials may be used.

Abstract: Low temperature wafer bonding process enhancement makes a wafer surface hydrophobic, preparing it with a buffered oxide etchant and then exposing it to H.sub.2 O.sub.2 before thermoelectric bonding. Has particular application to diaphragm-based pressure sensor construction.

Abstract: The formation of diaphragms by silicon wafer bonding provides for a structure having at least two such diaphragms with cavities in the wafers to which the diaphragm layer is bonded. Passageways through the wafers provide for communication of a fluid to the diaphragms. In some locations less than all of a plurality of diaphragms may be bonded to only one wafter having a cavity adjacent the diaphragm.