Micromechanical thermal-conductivity sensor having a porous cover
AssigneeRobert Bosch GmbH
InventorsMichael Arndt, Gerd Lorenz
Life of this patent
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Abstract
A micromechanical thermal-conductivity sensor is provided which includes a thermally insulated diaphragm formed by a recess in a base plate exhibiting poor thermal conductivity. At least one heating element is applied on the diaphragm, at least one temperature-dependent electrical resistor is applied on the diaphragm for measuring the temperature of the diaphragm, as well as at least one further temperature-dependent electrical resistor is applied outside of the diaphragm on the base plate for measuring the ambient temperature. On one or both of its sides, the diaphragm is covered by a porous cover plate permitting gas exchange by diffusion, a cavity being left open between the diaphragm and the porous cover plate.
Claims16
A micromechanical thermal-conductivity sensor, comprising:
- a thermally insulated diaphragm formed by a recess in a base plate exhibiting poor thermal conductivity;
- at least one heating element applied on the diaphragm;
- at least one temperature-dependent electrical resistor applied on the diaphragm for measuring a temperature of the diaphragm;
- and
- at least one further temperature-dependent electrical resistor applied outside the diaphragm on the base plate for measuring an ambient temperature;
- wherein the diaphragm is covered on at least one of its sides by a porous cover plate with a plurality of pores which permits gas exchange through diffusion, a cavity being left open between the diaphragm and the porous cover plate, the porous cover plate being secured on the base plate, and being made of at least one of a porous ceramic material or at least partially of porous silicon.
A method of using a micromechanical thermal-conductivity sensor, comprising:
- providing the micromechanical thermal conductivity sensor, the sensor including a thermally insulated diaphragm formed by a recess in a base plate exhibiting poor thermal conductivity;
- at least one heating element applied on the diaphragm;
- at least one temperature-dependent electrical resistor applied on the diaphragm for measuring a temperature of the diaphragm;
- at least one further temperature-dependent electrical resistor applied outside the diaphragm on the base plate for measuring an ambient temperature;
- wherein the diaphragm is being covered on at least one of its sides by a porous cover plate with a plurality of pores, the at least one porous cover plate which permits gas exchange through diffusion, a cavity being left open between the diaphragm and the porous cover plate, the porous cover plate being secured on the base plate, and the porous cover plate being made of at least one of a porous ceramic material or at least partially of porous silicon;
- and
- quantitatively analyzing one of a gas and a gas mixture using the sensor.
Dependencies are inferred from the claim text.