Gas sensor, manufacturing method, and detection method
AssigneeRobert Bosch GmbH
InventorsHelmut Grutzeck, Renate Mueller, Stefan Zehringer
Life of this patent
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Abstract
A gas sensor for detecting a physical and/or chemical value of an analysis gas, a corresponding manufacturing method, and operating method. The gas sensor is based on the principle of a thermal conductivity measurement with the aid of a sensor structure including a double meander structure made up of two resistor lines, as part of a Wheatstone bridge circuit, on a diaphragm of a substrate. The two resistor lines are energized in opposite directions as a function of the detected temperature. The physical and/or chemical value(s) of the analysis gas are/is subsequently determined as a function of the voltages detected at the double meander structure.
Claims12
A gas sensor for determining a physical and/or chemical value of an analysis gas using a thermal conductivity measurement, the gas sensor comprising:
- at least one first diaphragm including a first double meander structure made up of two resistor lines;
- an evaluator;
- and
- a second diaphragm that is separate from the first diaphragm, the second diaphragm including a second double meander structure made up of two resistor lines, and the second double meander structure having a resistance value that is different from the first double meander structure;
- wherein the resistor lines are energized in opposite directions for the thermal conductivity measurement, and the evaluator is configured to determine at least one physical and/or chemical value that represents a property of the analysis gas, as a function of detected voltages at the double meander structure as part of a Wheatstone bridge circuit.
A gas sensor for determining a physical and/or chemical value of an analysis gas using a thermal conductivity measurement, the gas sensor comprising:
- at least one first diaphragm including a first double meander structure made up of two resistor lines;
- an evaluator;
- and
- a second diaphragm that is separate from the first diaphragm, the second diaphragm including a second double meander structure made up of two resistor lines, and the second double meander structure having a resistance value that is different from the first double meander structure;
- wherein the resistor lines are energized in opposite directions for the thermal conductivity measurement, and the evaluator is configured to determine at least one physical and/or chemical value that represents a property of the analysis gas, as a function of detected voltages at the double meander structure as part of a Wheatstone bridge circuit,
- wherein a cavity is situated beneath the at least one first diaphragm, the at least one diaphragm being permeable to at least a portion of the analysis gas,
- wherein the evaluator is configured to determine the at least one physical and/or chemical value, which represents a property of the analysis gas, as a function of different voltages at the first and second double meander structures.
A method for manufacturing a gas sensor for determining a physical and/or chemical value of an analysis gas using a thermal conductivity measurement, the method comprising:
- creating at least one first diaphragm on a substrate using micromechanical methods;
- and
- creating a double meander structure made up of two resistor lines, as part of a Wheatstone bridge circuit, on the at least first diaphragm,
- wherein a cavity is created beneath the at least one diaphragm, the at least one diaphragm being created in such a way that it is permeable to at least a portion of the analysis gas,
- wherein the at least one diaphragm and/or the cavity is situated on a structure that is stress-decoupled with respect to a frame,
- wherein the stress decoupling of the structure takes place in the substrate via the creation of a bridge that is stepped and/or fastened to one side of the frame, it being provided that electrical supply lines for the resistor lines are created on the bridge.
A method for determining a physical and/or chemical value of an analysis gas using a thermal conductivity measurement, for use in an evaluation unit of a gas sensor, comprising the following steps:
- for the thermal conductivity measurement, energizing two resistor lines of a first double meander structure on a first diaphragm in opposite directions;
- and
- determining at least one physical and/or chemical value that represents a property of the analysis gas, as a function of detected voltages at the double meander structure as part of a Wheatstone bridge circuit,
- wherein the gas sensor includes a second diaphragm that is separate from the first diaphragm, the second diaphragm including a second double meander structure made up of two resistor lines, and the second double meander structure having a resistance value that is different from the first double meander structure.
A method for determining a physical and/or chemical value of an analysis gas using a thermal conductivity measurement, for use in an evaluation unit of a gas sensor, comprising the following steps:
- for the thermal conductivity measurement, energizing two resistor lines of a first double meander structure on a first diaphragm in opposite directions;
- and
- determining at least one physical and/or chemical value that represents a property of the analysis gas, as a function of detected voltages at the double meander structure as part of a Wheatstone bridge circuit,
- wherein the gas sensor includes a second diaphragm that is separate from the first diaphragm, the second diaphragm including a second double meander structure made up of two resistor lines, and the second double meander structure having a resistance value that is different from the first double meander structure, and wherein the determining of the at least one physical and/or chemical value, which represents the property of the analysis gas, is as a function of different voltages at the first and second double meander structures.
Dependencies are inferred from the claim text.