Sealed capacitive pressure sensors

A micromachined pressure sensor comprising:

• (a) a microstructure substrate;
• b) a microstructure base formed as a hollow cylinder which is closed secured and sealed to the substrate at a lower end of the base;
• (c) a microstructure diaphragm secured and sealed to the base at an upper end of the base above the substrate to define a cavity with the base and a surface of the substrate that is sealed between the base, substrate and diaphragm;
• (d) a skirt extending outwardly from the base and the cavity above the substrate with at least one of the diaphragm or the base deforming and deflecting with changes between ambient pressure and pressure within the sealed cavity to change a volume of the sealed cavity and to deflect the skirt;
• and
• (e) a first electrode formed on the skirt to deflect with the skirt and an adjacent second electrode on the substrate such that deflection of the skirt with changes in pressure changes the effective capacitance between the electrodes, wherein at least a portion of the electrodes are formed external to the sealed cavity such that electrical leads adapted to be connected to the electrodes external to the sealed cavity.

A micromachined pressure sensor comprising:

• (a) a microstructure substrate;
• (b) a microstructure base which is closed, secured and sealed to the substrate at a lower end of the base;
• (c) a microstructure diaphragm secured and sealed to the base at an upper end of the base to define a cavity with the base and a surface of the substrate that is sealed between the base, substrate and diaphragm, at least one of the diaphragm or base deforming and deflecting with changes between ambient pressure and pressure within the sealed cavity to change a volume of the sealed cavity;
• (d) a first electrode formed on at least one of the diaphragm or the base outside the cavity to deflect therewith, and a second electrode mounted adjacent thereto to form a capacitor with the first electrode such that the effective capacitance between the electrodes changes as the first electrode is deflected in a manner which is related to changes in pressure, wherein at least a portion of the second electrode is formed external to the sealed cavity such that electrical leads adapted to be connected to the electrodes external to the sealed cavity.

A micromachined pressure sensor comprising:

• (a) a microstructure substrate;
• (b) a microstructure base formed as a hollow cylinder which is closed, secured and sealed to the substrate at a lower end of the base;
• (c) a microstructure diaphragm secured and sealed to the base at an upper end of the base above the substrate to define a cavity with the base and a surface of the substrate between the base, substrate and diaphragm;
• (d) a skirt extending outwardly from the base above the substrate with at least the diaphragm deforming and deflecting with changes in pressure across the diaphragm to change a volume of the sealed cavity and to deflect the skirt;
• and
• (e) a first electrode formed on the skirt to deflect with the skirt and an adjacent second electrode on the substrate such that deflection of the skirt with changes in pressure changes the effective capacitance between the electrodes, wherein at least a portion of the electrodes are formed external to the sealed cavity such that electrical leads adapted to be connected to the electrodes external to the sealed cavity.