Design of a wet/wet amplified differential pressure sensor based on silicon piezoresistive technology

A method of producing a pressure sensor package which comprises:

• a) providing a housing having a first cavity and a second cavity within the housing, and a wall member separating the first cavity and the second cavity;
• b) positioning a conductive elastomeric pad within the first cavity;
• c) positioning a pressure sensor on the conductive elastomeric pad;
• d) positioning an elastomeric media seal on the pressure sensor;
• e) attaching a pressure cap to the housing over the elastomeric seal, such that the pressure cap and the housing together form a hermetic seal which prevents the escape or entry of a gas through the hermetic seal;
• said pressure cap further having a port therethrough for admitting a gas under pressure into the first cavity;
• f) positioning a signal amplifier within the second cavity, and then positioning a cover on the second cavity which encloses the signal amplifier within the second cavity;
• g) providing an electrical connector through the wall member and forming an electrical connection between the pressure sensor and the signal amplifier;
• h) providing a lead frame comprising a plurality of electrical connectors extending through the housing, and forming electrical connections between the lead frame and the pressure sensor and between the lead frame and the signal amplifier.

A method of determining the pressure of a fluid which comprises:

• i) providing a pressure sensor package which comprises:
• a) a housing having a first cavity and a second cavity within the housing, and a wall member separating the first cavity and the second cavity;
• b) a conductive elastomeric seal pad positioned within the first cavity;
• c) a pressure sensor positioned on the conductive elastomeric pad;
• d) an elastomeric media seal positioned on the pressure sensor;
• e) a pressure cap on the elastomeric media seal, which pressure cap is attached to the housing such that the pressure cap and the housing together form a hermetic seal which prevents the escape or entry of a gas through the hermetic seal;
• said pressure cap further having a port therethrough for admitting a gas under pressure into the first cavity;
• f) a signal amplifier positioned within the second cavity, and a cover on the second cavity which encloses the signal amplifier within the second cavity;
• g) an electrical connector through the wall member forming an electrical connection between the pressure sensor and the signal amplifier;
• h) a lead frame comprising a plurality of electrical connectors extending through the housing, said lead frame forming electrical connections with the pressure sensor and the signal amplifier;
• ii) flowing a fluid through the port into the first cavity;
• iii) measuring the pressure of the fluid in the cavity with the pressure sensor and issuing an electrical signal corresponding to the measured pressure from the pressure sensor to the signal amplifier;
• iv) amplifying the electrical signal corresponding to the measured pressure from the pressure sensor with the signal amplifier to form an amplified signal, and issuing the amplified signal to an electrical connection with the lead frame;
• v) presenting indicia corresponding to the measured pressure on a display electrically connected to the lead frame.