Abstract: A diffusion bonded space-conserving integrated fluid delivery system which is particularly useful for gas distribution in semiconductor processing equipment. The disclosure includes an integrated fluid flow network architecture, which may include, in addition to a layered substrate containing fluid flow channels, various fluid handling and monitoring components. A capacitive dual electrode pressure sensor which is integrated into a multilayered substrate is described. The pressure sensor may be used as a gage relative to atmospheric pressure if desired for a particular application.

Abstract: A capacitive pressure sensor and method for its fabrication. The sensor is fabricated from first and second wafers to have a mechanical capacitor comprising a fixed electrode and a moving electrode defined by a conductive plate. The sensor further has a diaphragm on a surface of the first wafer that is mechanically coupled but electrically insulated from the conductive plate. A conductive layer on the surface of the first wafer is spaced apart from the conductive plate to define the fixed electrode. The second wafer is bonded to the first wafer and carries interface circuitry for the sensor, including the conductive plate and the fixed electrode which are between the first and second wafers and electrically connected to the interface circuitry. At least an opening is present in the first wafer and its first conductive layer by which the diaphragm is released and exposed to an environment surrounding the sensor.

Abstract: There is provided a pressure sensor having: a sensor chip (30) which detects a pressure; a base plate (20 (21, 22)) which supports the sensor chip (30); and a support diaphragm (50) which is bonded to the base plate (20 (21, 22)) and supports the base plate (20 (21, 22)), wherein the pressure sensor (1) has a structure in which the support diaphragm (50) is joined to a package (10), and the sensor chip (30) and the base plate (20 (21, 22)) are supported in the package through the support diaphragm (50) alone, thereby constantly and accurately detecting a pressure without being affected by a heat stress caused due to heat from the outside.

Abstract: A capacitive pressure sensor includes a substrate assembly having a conductive layer. A conductive membrane is mounted to the substrate assembly so that a sealed reference chamber is defined by the conductive membrane and the substrate assembly. A cap is arranged on the substrate assembly and defines one or more apertures so that an antechamber is defined between the cap and the conductive membrane. Differential pressure between the reference chamber and antechamber can cause deflection of the conductive membrane which, in turn, varies the capacitance between the conductive membrane and the conductive layer.

Abstract: A sensor preferably capable of high resolution sensing over a large operating range includes a composite diaphragm containing nanotubes or nanowires. The nanotubes or nanowires preferably form a mat that is embedded in insulating material, such as high dielectric or insulating thin films. The nanotubes or nanowires may provide the diaphragm with a Young's modulus of greater than about 1000 GPa and a tensile strength of greater than about 100 GPa. The strain in the nanotubes or nanowires may be measured by a change in resistance, voltage, current or capacitance.

Abstract: A pressure sensor for sensing a pressure of a process fluid includes a sensor body having a cavity formed therein. A deflectable diaphragm is positioned in the cavity and deflects in response to a pressure applied to the cavity. An electrode on the diaphragm forms a variable capacitor with the pressure sensor body. The capacitance varies in response to the applied pressure.

Abstract: A pressure sensor includes a structure that deforms in response to an applied pressure. A light source is directed at the structure. This provides a reflection from the structure. A sensor is arranged to sense the reflection and provide an output related to the applied pressure.

Abstract: Methods for making and systems employing pressure and temperature sensors are described. Embodiments include a capacitive element including a first conductor plate and a second conductor plate. Each plate includes a conductor layer formed on a substrate. In a pressure sensor embodiment, seal is positioned at or near the edges of the conductor plates, and a gas retained in a gap defined between the plates. In a temperature sensor embodiment, the gap defined between the plates is in fluid communication with the external environment.

Abstract: A transducing system includes a support structure configured to support a transducer and includes at least one environmental sensor carried by the support structure. The environmental sensor may be a humidity sensor, a temperature sensor, an altitude sensor, or a combination of these.

Abstract: The invention provides for a method of sensing pressure with a pressure sensor having a sensor membrane and a compensation membrane. The pressure sensor also includes a power supply, a controller; and a charge amplifier, a charge injector and two switches arranged in signal communication with the controller. The method includes the step of connecting the charge amplifier to the switches via a sensor capacitor Cs in parallel with a reference capacitor Cr in parallel with a parasitic capacitance Cp to ground, the charge injector and charge amplifier arranged in parallel connection between the capacitors and the controller. The method also includes the step of operating the switches, via the controller, to determine a charge imbalance indicative of a pressure difference between the sensor and compensation membranes.

Abstract: The invention relates to a flexible, resilient capacitive sensor suitable for large-scale manufacturing. The sensor comprises a dielectric, an electrically conductive layer on the first side of the dielectric layer, an electrically conductive layer on a second side of the dielectric layer, and a capacitance meter electrically connected to the two conductive layers to detect changes in capacitance upon application of a force to the detector. The conductive layers are configured to determine the position of the applied force. The sensor may be shielded to reduce the effects of outside interference.

Abstract: A variable capacitance measuring device can comprise any one or more features in various different embodiments allow a reliable, compact device to be achieved. A capacitor electrode, a gettering housing, and pinch-off connector may be aligned along a common axis may reduce width dimensions without a substantial increase in length. Temperature-induced variations may be reduced by selecting materials that have coefficients of thermal expansion relatively closer to one another. Substantially varying topologies for ceramic-metal interfaces may reduce the likelihood of external contaminants from reaching the evacuated portion of the device. A tube can be used between the capacitor portion and a gettering housing to isolate external forces and getter activation heat from the sensor. The same tube also reduces heat loss from a heated sensor and protects the electronics from overheating. Embodiments also include processes for using and forming the devices.

Abstract: A capacitive pressure sensor of substantially ceramic material comprises a thick base plate (100), a front plate (140) having the same thickness as the base plate and a movable diaphragm (120) located between the front plate and the base plate. Capacitor electrodes (121b, 121a) are provided at the surface of the diaphragm facing the base plate and form a measurement capacitor. The diaphragm (120) is extremely thin and is produced by sintering a ceramic material such aluminum oxide. Owing to a pressing process used during the sintering a strong, very thin diaphragm is obtained having no mechanical stresses and fracture indications. It can be produced to have a very small thickness in order to provide pressure sensors having a high sensitivity, which can also for high-vacuum applications tolerate to be subjected to the atmospheric pressure. A shielding plate (110) can be inserted between the base plate (100) compensating the measurement capacitor.

Abstract: A capacitive pressure sensor includes a electrically conductive, generally piston shaped diaphragm with a flexible base wall configured to deflect under pressure. The diaphragm is generally U-shaped in cross section. The base wall includes an upper, flat sensing surface which acts as a capacitive electrode. The diaphragm further includes a step around a radially-outermost perimeter which is elevated from the flat sensing surface. A sensing electrode body is located on top of the step and creates a capacitive sensing cavity between the sensing surface and the bottom surface of the electrode body. On the bottom surface of the electrode body is formed a center, circular electrode and a ring electrode that surrounds the center electrode. The center electrode and the sensing surface form a variable capacitor which changes with pressure and the ring electrode and the sensing surface form a reference capacitor.

Abstract: A pressure sensor for sensing a fluid pressure comprising: a first chamber including a first conductive membrane, wherein a fluid is sealed within the first chamber at a reference pressure such that the first conductive membrane deflects from pressure differences between the reference and the fluid pressure; a second chamber including a second conductive membrane sealed from the fluid pressure, wherein the second membrane deflects in response to a change in temperature which the pressure sensor is exposed thereto; and a circuit in electrical communication with the first and second conductive membrane, the circuit being configured to obtain a first and second signal from the first and second conductive membranes respectively, the first and second signals being indicative of the deflection of the first and second conductive membranes, wherein the circuit adjusts the first signal by the second signal to generate an output signal indicative of the fluid pressure.

Abstract: A control for pressurizing a load lock. The control initiates pressurization of the loadlock interior by coupling a source of gas to the loadlock interior. A representative load lock includes a pressure sensor and multiple valves to atmosphere where at least one such valves is a passthrough valve for removal of and insertion of workpieces from and into a load lock interior. A second fast acting valve also opens to atmosphere. A pressure rise inside the loadlock interior is monitored and when the pressure reaches a threshold pressure above atmosphere the fast acting valve is opened to atmosphere. This second fast acting valve is configured to relieve overpressure from the passthrough valve prior to opening of said passthrough valve. Workpiece movement is accomplished with the aid of a robot which reaches into the loadlock interior as it is either depositing workpieces or retrieving them.

Abstract: A pressure sensing system formed in a monolithic semiconductor substrate. The pressure sensing system comprises a pressure sensing device formed on the monolithic semiconductor substrate. The pressure sensing device is adapted to be disposed in an environment for developing an electrical pressure signal corresponding to the pressure in the environment. The system includes driver circuitry formed in the monolithic semiconductor substrate. The driver circuitry is responsive to input electrical signal for generating an output pressure signal. A conductive interconnect structure formed in the monolithic semiconductor substrate to electrically connects the pressure sensing device to the driver circuitry such that electrical pressure signals developed by the pressure sensing device are provided as input electrical signals to the driver circuitry.

Abstract: To accurately set a detection axis of a sensor even when the sensor is attached to an inclined surface, provided is: a sensor responsive to an operation to a predetermined detection axis. A sensor device accommodates this sensor 1 and is a lead provided for conduction between a terminal of this sensor device and a mounting board. A mold for fixing the sensor device to set the detection axis of the sensor and a bottom surface of the mold with a desired angle is also provided.

Abstract: The pressure sensor device has a laminated diaphragm (12) in which a strain resistance gauge is formed in a surface and a stopper member (13) including a concave portion forming a curved surface parallel to a surface formed by displacement of the diaphragm, the concave portion being disposed to face the diaphragm. Specifically, the concave portion of the stopper member is formed into a curved surface in which depth y at a distance x from the center of the diaphragm is expressed by a quartic function [y=pr4(1?x2/r2)2/64D] in relation to the operating pressure for protection against maximum pressure p when the diaphragm has a radius of r, a thickness of t, and a flexural rigidity of D.

Abstract: A pressure actuated switch for a pressure control region includes a diaphragm with a first electrically conductive surface and a second conductive surface electrically isolated from the first conductive surface. The switch also includes an evacuated cavity disposed between the first conductive surface and the second conductive surface and includes a piezoelectric assembly on which is mounted the second conductive surface. A controller applies a control signal to the piezoelectric assembly. The piezoelectric assembly in response to the control signal translates the second conductive surface to set a trip point of the switch. The diaphragm is exposed to the pressure of the pressure control region. In response to the pressure applied to the first conductive surface, the first conductive surface deflects in a direction toward the second conductive surface. The first conductive surface communicates with the second conductive surface to produce a signal when the applied pressure is sufficiently large.

Abstract: A pressure-sensor package mainly includes a pressure sensor, a support substrate, and a resin layer. The pressure sensor includes a glass substrate having a fixed electrode, and a silicon substrate having a diaphragm that is disposed apart from the fixed electrode by a predetermined distance. The support substrate is a silicon/glass composite substrate on which the pressure sensor is mounted such that the support substrate and the diaphragm face each other. The resin layer fixes the pressure sensor and the support substrate together. The pressure sensor is mounted on a mounting area of the support substrate with a joint member therebetween. Accordingly, even if a gap between the support substrate and the diaphragm has a size of about several micrometers, the pressure-sensor package is capable of performing pressure detection with high sensitivity.

Abstract: A capacitive sensor including a housing having a hermetically sealed cavity, a plate in the cavity, a diaphragm forming a part of the cavity and spaced from the plate, a conductive layer on the first diaphragm, and a second conductive layer on the plate, the first and second conductive layers being the electrodes of a capacitor whose capacitance varies with the position of the diaphragm relative to the plate.

Abstract: A pressure sensor (30) for sensing a fluid pressure in harsh environments such as the air pressure in a tire, by using a chamber (58) partially defined by a flexible membrane (50), the flexible membrane (50) is a laminate having at least two layers wherein at least one of the layers is at least partially formed from conductive material, and the chamber (58) containing a fluid at a reference pressure, such that the flexible membrane (50) deflects from any pressure difference between the reference pressure and the fluid pressure; and, associated circuitry (34) for converting deflection of the flexible membrane (50) into an output signal indicative of the fluid pressure. Forming the membrane from a number of separately deposited layers alleviates internal stress in the membrane (50). The layers can be different materials specifically selected to withstand harsh environments.

Abstract: A variable capacitor, a microfabricated implantable pressure sensor including a variable capacitor and an inductor, and related pressure measurement and implantation methods. The inductor may have a fixed or variable inductance. A variable capacitor and pressure sensors include a flexible member that is disposed on a substrate and defines a chamber. Capacitor elements extend indirectly from the flexible member. Sufficient fluidic pressure applied to an exterior surface of the flexible member causes the flexible member to move or deform, thus causing the capacitance and/or inductance to change. Resulting changes in resonant frequency or impedance can be detected to determine pressure, e.g., intraocular pressure.

Abstract: A pressure sensor assembly for sensing a pressure of a process fluid includes a sensor body having a cavity formed therein to couple to a process fluid pressure. A deflectable diaphragm in the cavity deflects in response to the first and second process fluid pressures. A first primary electrode couples to a wall of the cavity and forms a first primary capacitor between the first primary electrode and the deflectable diaphragm. A first secondary electrode couples to the wall of the cavity to form a first secondary capacitor between the first secondary electrode and the deflectable diaphragm. A second primary electrode and second secondary electrode are preferably coupled to a wall of the cavity opposite the first. Line pressure of the process fluid is determined based upon variation in the secondary capacitors relative to the primary capacitors.

Abstract: A pressure sensor having a predetermined chamber dome angle with an electrode. A hole is located in the top to provide pressure readings and the bottom has an input port. A primary diaphragm is coated on both sides with an electrode and an insulator. A secondary diaphragm is coated on the side which faces the primary diaphragm. Offset holes are made in the two diaphragms which permits pressure equalization during self calibration. Both diaphragms are initially energized to seal the gage volume, and then the secondary diaphragm is used to self calibrate using a known pressure.

Abstract: A sensor and sensor module with small power consumption and high reliability are disclosed. The sensor includes a capacitor having a capacitance varying with a physical quantity, a capacitance-voltage conversion circuit for converting the capacitance of the capacitor into a voltage, and a control signal generation circuit for generating a plurality of control signals. The capacitor has a frequency-capacitance characteristic with a resonant frequency. In a measurement of the physical quantity, the capacitance of the capacitor is measured with one of the control signals having a first frequency which is much higher or much lower than the resonant frequency. In a self-diagnosis of the sensor, the capacitance of the capacitor is measured with another one of the control signals having a second frequency which is equal or close to the resonant frequency.

Abstract: A two phase, second order capacitance-to-digital (CD) modulator includes a first stage sigma-delta integrator that forms charge packets as a function of sensor capacitance during an auto-zero phase and integrates the packets during an integration phase to produce an output voltage. The first stage integrator holds its output voltage during the auto-zero phase, so that a second stage sigma-delta integrator can sample the first stage output voltage during the auto-zero phase and integrate the sampled voltage during the integration phase.

Abstract: A capacitance-to-digital (CD) modulator converts capacitance of a differential pressure sensor to a pulse code modulation output signal. The first stage of the CD modulator is a sigma-delta integrator having an auto-zero capacitor connected between an integrator input node and an amplifier input. During an auto-zero phase, a feedback capacitor is connected between the amplifier input and output, and the auto-zero capacitor stores a voltage that is a function of leakage resistance of the sensor capacitor connected to the integrator input node. During an integration phase, the feedback capacitor is connected to the integrator input node. If an overpressure/short circuit condition exists, the stored voltage on the auto-zero capacitor induces a current to flow to the feedback capacitor to drive the integrator to saturation and suppress foldback anomaly.

Abstract: The axial distance between opposing conductors of a capacitance pressure transducer can depend, in part, upon the thickness of a seal that is disposed between a housing and a diaphragm of the capacitance pressure transducer. The present invention utilizes spacer elements and sealing beads to form a seal that is disposed between the housing and the diaphragm of a capacitance pressure transducer. The sealing beads have a melting temperature that is lower than the melting temperature of the spacer elements. The sealing beads are melted so that they flow around and surround the unmelted spacer elements. Upon solidifying, the sealing beads and the spacer elements thus form the seal. The thickness of the seal can be established accurately and uniformly by controlling the height of the spacer elements.

Abstract: A diagnostic system for a pressure sensor having a cavity configured to receive on applied pressure is provided. The cavity has a first and a second wall. A deflectable diaphragm is positioned in the cavity and configured to form a first and a second capacitance with the first wall and a third and a fourth capacitance with the second wall which change in response to the applied pressure. The capacitances form a first transfer function and a second transfer function. Changes in the first transfer function relative to the second transfer function are detected to provide a diagnostic output.

Abstract: A pressure sensor includes a structure that deforms in response to an applied pressure. A light source is directed at the structure. This provides a reflection from the structure. A sensor is arranged to sense the reflection and provide an output related to the applied pressure.

Abstract: A process for producing a plate for a capacitive sensor element. In one embodiment of the present invention, a method includes forming a plate from a substantially pure aluminum oxide slurry, heating the plate a first time in an oven to sinter the plate, cooling the plate after the heating step, heating the plate a second time to smooth the plate, and cooling the plate after the second heating.

Abstract: A diaphragm pressure sensor includes a first insulating substrate, a conductive substrate with a diaphragm, and a second insulating substrate with a gas inlet are bonded so as to form a pressure reference room between the diaphragm and the first insulating substrate and a pressure measuring room between the diaphragm and the second insulating substrate. The deformation of the diaphragm caused by the pressure difference between the pressure measuring room and the pressure reference room is measured to obtain the pressure of a space which is communicated with the pressure measuring room through the gas inlet. Furthermore, a plate is adhered to a surface of at least one of the first and second insulating substrates and the plate has a lower thermal expansion rate in an ambient temperature than that of the insulating substrate to which the plate is adhered.

Abstract: The disclosed pressure transducer assembly includes a housing, a pressure sensor disposed within the housing, a coupling establishing a sealed pathway between the housing and an external source of gas or fluid, and a deposition trap disposed in the pathway. The deposition trap provides a plurality of channels, each of the channels being narrower than the pathway.

Abstract: The invention relates to measuring devices for the measuring of pressure, and more specifically to capacitive pressure sensors. The silicon crystal planes {111} are located at the corners of a wet etched membrane well of a pressure sensor element according to the present invention. An object of the invention is to provide an improved method of manufacturing a capacitive pressure sensor, and a capacitive pressure sensor suitable for use, in particular, in small capacitive pressure sensor solutions.

Abstract: A microfluidic device and method for capacitive sensing. The device includes a fluid channel including an inlet at a first end and an outlet at a second end, a cavity region coupled to the fluid channel, and a polymer based membrane coupled between the fluid channel and the cavity region. Additionally, the device includes a first capacitor electrode coupled to the membrane, a second capacitor electrode coupled to the cavity region and physically separated from the first capacitor electrode by at least the cavity region, and an electrical power source coupled between the first capacitor electrode and the second capacitor electrode and causing an electric field at least within the cavity region. The polymer based membrane includes a polymer.

Abstract: For minimizing the span error of a pressure sensor having an essentially cylindrical platform and a measuring membrane joined to an end face of the platform, with the pressure measuring cell being axially clamped between an elastic sealing ring, which bears against the membrane-bearing end face of the pressure measuring cell, and a support ring, which bears against the rear face of the pressure measuring cell, the dimensions of the support ring are coordinated with the dimensions of the sealing ring and pressure measuring cell such that a radial deformation of the membrane-bearing end face caused by the axial clamping of the pressure measuring cell is sufficiently small that the span error of the pressure sensor arising from a reduction of the axial clamping force by at least 10% amounts to not more than about 0.02%. Additionally, arranged between the support ring and a clamping ring is a stiff decoupling element, which minimizes the temperature hysteresis of the span.

Abstract: A tire condition detecting system has transmitters and a receiver. The transmitter is installed in a plurality of wheels and the receiver is installed in a chassis of a vehicle. The receiver has a controller which determines transmission timings in which a transmitting/receiving unit transmits the electrical wave for electrical charging to the transmitters. Moreover the controller detects an electrical wave from a nearby vehicle at the transmission timing. If the detected wave from the nearby vehicle is stronger, the controller waits for a predetermined period before making the transmitting/receiving unit transmit the electrical wave.

Abstract: A pressure sensor (30) for sensing fluid pressure in harsh environments such as the air pressure in a tire by providing a chamber (58) partially defined by a flexible membrane (50). The flexible membrane (50) is at least partially formed from conductive material, and the chamber (58) contains a fluid at a reference pressure. The flexible membrane (50) deflects from any pressure difference between the reference pressure and the fluid pressure. A conductive layer (36) within the chamber spaced from the flexible membrane (50) and, associated circuitry (34) incorporating the flexible membrane (50) and the conductive layer (36). The conductive layer (36) and the flexible membrane (50) form capacitor electrodes and the deflection of the flexible membrane (50) changes the capacitance which the associated circuitry (34) converts into an output signal indicative of the fluid pressure.

Abstract: According to the present invention, there is provided a high-precision differential pressure sensor which is not affected by a considerable change in baseline pressure. A differential pressure sensor of the present invention includes: a pair of diaphragms, each including a diaphragm portion capable of being deformed due to application of a pressure and a support portion for holding an outer peripheral edge of the diaphragm portion; a pair of fixed electrodes in disk-like form fixed to the support portions of the diaphragms; and a movable electrode including a disk-like electrode portion and shaft-like projections extending in opposite directions from a central portion of the electrode portion. The shaft-like projections extend at a right angle relative to the electrode portion, and the movable electrode is secured to central portions of the diaphragms through the shaft-like projections so that the electrode portion faces each of the fixed electrodes in a predetermined spaced relationship.

Abstract: A pressure sensing device (10, 40) is shown having a ceramic capacitive sensing element (12) received in a chamber formed in a hexport housing (16). The hexport housing has a fluid passageway (16c) communicating with a recessed chamber (16d) formed in a bottom wall circumscribed by an annular platform shoulder (16e). A thin flexible metal diaphragm (18) is hermetically attached to the bottom wall along the platform shoulder. A curable adhesive resin having a thermal coefficient of expansion and modulus of elasticity appropriately matching that of sensing element (12), such as polyurethane, is cast between the sensing element (12) and the metal diaphragm (18) forming, when cured, a layer bonded to both members resulting in a sensor that is effective in monitoring negative as well as positive fluid pressures.

Abstract: A wireless pressure sensor system has a pressure sensing capacitor and an inductor mounted on a common housing. The pressure sensing capacitor has a conductive diaphragm, a dielectric layer and a fixed electrode separated at least in part from the diaphragm by a gap formed in the housing. The electrode is arranged with a protrusion such that displacement of the diaphragm varies the area of capacitive contact with the electrode by rolling along the protrusion. The inductor coil and pressure sensing capacitor are connected to form a passive inductive-capacitive (LC) tank circuit. A remote interrogation circuit, inductively coupled to the pressure sensor inductor coil can be utilized to detect the resonant frequency of the LC tank which varies as a function of pressure sensed by the diaphragm.

Abstract: A pressure sensor includes: a measuring cell having a base plate and a measuring membrane connected along its edge with the base plate, and means for generating an electrical quantity dependent on deformation of the measuring membrane; a circuit for registering the electrical quantity; and a capsule having a capsule body and a sealing element, with which the capsule is hermetically sealed along a joint. The capsule encloses the circuit, in order to protect such from influences of moisture; and the joint of the capsule is mechanically decoupled from the base plate. The mechanical decoupling of the joint means, for example, that at least the axial support of the pressure measuring cell in a housing is not allowed to be transferred through the joint. Despite arranging of the capsule on the base plate, pressure-related and temperature-related distortions of the base plate are not permitted to have any effects on the joint of the capsule.

Abstract: A capacitive load cell includes upper and lower capacitor plates and an intermediate array of dielectric pads formed of silicone-impregnated open-cell urethane foam (i.e., gel pads). The silicone essentially displaces air that would otherwise be trapped in the foam, contributing to a dielectric having minimal humidity-related variability. The upper capacitor plate is defined by an array of individual charge plates, the lower capacitor plate defines a ground plane conductor common to each of the charge plates, and the dielectric pads are disposed between the ground plane conductor and each of the charge plates, leaving channels between adjacent dielectric pads. When occupant weight is applied to the seat, the dielectric pads transmitting the weight distend laterally into the channels to reduce the separation between the respective upper and lower capacitor plates, and the consequent change in capacitance is detected as a measure of the applied force and the force distribution.

Abstract: For minimizing the span error of a pressure sensor having an essentially cylindrical platform and a measuring membrane joined to an end face of the platform, wherein the pressure measuring cell is axially clamped between an elastic sealing ring, which bears against the membrane-containing, end face of the pressure measuring cell, and a support ring, which supports the measuring cell on the rear side thereof, the dimensions of the support ring are matched to the dimensions of the sealing ring and the pressure measuring cell in such a way that a radial deformation of the membrane-containing end face resulting from the axial clamping of the pressure measuring cell is sufficiently small that the span error of the pressure sensor because of a reduction of the axial clamping force by a least 10% amounts to not more than 0.02%. The geometry of the support ring is determined iteratively by means of the FEM.

Abstract: A capacitive-type sensor comprises a glass plate having an electrode formed thereon, and a micromachined structure formed from a semiconductor material and having an insulating rim formed thereon. A conducting seal is formed on the insulating rim and arranged to be bonded to the glass substrate to define an enclosed cavity containing the electrode, to thereby define a capacitive element, the conducting seal being arranged, in use, to have an electrical signal passed there through to determine a capacitance thereof which is indicative of the parameter to be determined by the sensor.

Abstract: A capacitive vacuum measuring cell includes first and second ceramic housing bodies (1, 4) joined by an edge seal (3). A thin ceramic membrane (2) is supported between first and second housing bodies (1, 4) by the edge seal (3) at a small distance from the first housing body (1) creating a reference vacuum chamber (25) therebetween. An electrically conductive material (7) coats opposing surfaces of the first housing body (1) and the membrane (2) to form a capacitor. A measurement vacuum chamber (26) is provided between the membrane (2) and the second housing body (4). A port (5) communicates with the second housing body (4) to connect the measurement vacuum chamber (26) of the measuring cell to the medium to be measured. The membrane (2) is made from an Al2O3 slurry that is sintered in a first heating step, cooled, and then reheated to smooth the membrane.

Abstract: A pressure sensor (30) for harsh environments such as vehicle tires, formed from a chamber (58) partially defined by a flexible membrane (50), the chamber (58) containing a fluid at a reference pressure. In use, the flexible membrane (50) deflects due to pressure differentials between the reference pressure and the fluid pressure, the membrane being at least partially formed from conductive material. A conductive layer (36) is deposited within the chamber (58) spaced from the flexible membrane (50) such that they form opposing electrodes of a capacitor. Associated circuitry (34) is also deposited for converting the deflection of the flexible membrane (50) into an output signal indicative of the fluid pressure. The membrane (50) is at least partially formed from a transition metal nitride because transition metal nitrides are a metal ceramics with high yield strength and metallic bonding that makes it suitable for use in extreme environments.

Abstract: The present invention is directed at methods and apparatuses for facilitating the establishment of a reference pressure within a reference chamber of a pressure transducer. The transducer has a housing and a cover, the housing defining a reference chamber and an aperture. A meltable sealing material is disposed on at least one of the cover and the housing. The apparatus includes a pressure chamber that is rotatable between a first position and a second position, a pressure source that is connected to the pressure chamber, a guide that is attachable to the transducer near the aperture, and a heater for selectively heating the pressure chamber to a temperature sufficiently high to melt the sealing material. The cover is positioned in an internal space of the guide. The guide is attached to the transducer near the aperture.