A method of making a low-cost metal diaphragm sensor that integrates both
pressure and temperature sensing in a single sensor assembly utilizes
thick-film processing to form a circuit including stress and temperature
sensitive elements on the outboard or exposed surface of a thin metal
diaphragm separating the circuit from a pressurized fluid. Only a thin
layer of dielectric separates the stress and temperature sensitive
elements from the diaphragm surface. The stress sensitive elements respond
to mechanical stressing of the diaphragm due to the presence of the
pressurized fluid, while the temperature sensitive element responds to the
temperature of the pressurized fluid. The thermal capacity of the fluid
greatly exceeds that of the diaphragm, so that the temperature responsive
characteristic of the temperature sensitive element accurately reflects
the temperature of the pressurized fluid.
