Patent ID: 6330829
Filing Date: 2001-12-18
Classification: G01L

Abstract:
An oil-filled differential pressure transducer comprising:a housing including a first end containing a first recess, an oppositely disposed second end containing a second recess, and first and second isolation diaphragms respectively enclosing said first and second recesses and forming in conjunction therewith first and second oil-filled cavities;first and second headers secured within said housing and being electrically coupled together, said first header including a plurality of pins and a central aperture opening there through; and,a dielectrically isolated, lead-less sensor mounted to said first header, said sensor including:a sculptured silicon wafer including first and second surfaces and a deflectable diaphragm;a P+ region formed on said first surface of said silicon wafer and including a plurality of serpentine resistors formed into a Wheatstone Bridge on the deflectable diaphragm, a group of large contact areas leading from the Wheatstone Bridge, and a rim surrounding and electrically isolated from the contact areas; and,a first glass wafer sealed to at least part of said P+ region, said first glass wafer including a central channel and a plurality of apertures opening there through, each of said apertures being filled with a glass-metal frit adapted to make electrical contact to an associated one of said contact areas and a corresponding one of said pins of said first header;whereby, a first pressure applied to said first diaphragm is communicated to said sensor through said first oil-filled cavity, central aperture of said first header and central channel of said first glass wafer, and a second pressure applied to said second diaphragm is communicated to said sensor through said second oil-filled cavity, such that said first and second pressures are applied to opposite sides of the sensor, and a resulting deflection of said diaphragm is indicative of a difference between said first and second pressures.