Gas Sensor Electrode Stabilization via Voltage Decomposition
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Solution Overview
Problem
Existing gas sensor production methods face challenges in stabilizing electrode conditions, leading to unreliable sensitivity characteristics and reduced production yield due to variations in oxidation and reduction states during the aging process, which can result in erroneous product determinations and decreased measurement accuracy.
Innovation Solution
A method involving the formation of a sensor element with an oxygen-ion conductive solid electrolyte layer, where a wiring pattern is printed on ceramic green sheets, laminated, baked, and then subjected to a reducing atmosphere, followed by voltage application between electrodes to decompose and remove residual gases, ensuring stable electrode conditions before electrical characteristic inspection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-treatment process is performed by driving the sensor element in a mixed gas atmosphere for a predetermined time period, then the electrode condition is stabilized, but the production time is increased and productivity is reduced
Solution Approach 1:
The patent replaces the conventional pre-treatment method using a mixed gas atmosphere (chemical method) with a vacuum drying method (physical method). By applying vacuum and heating to evaporate residual organic substances, the electrode condition is stabilized without requiring extended mixed gas exposure time, thus reducing production time while maintaining reliability
Solution Approach 2:
The patent changes the pre-treatment parameters from mixed gas atmosphere composition and exposure duration to vacuum degree and heating temperature. This parameter substitution allows for more controlled and time-efficient stabilization of the electrode condition, improving productivity while achieving the same reliability outcome
2Productivity
If the electrode condition is not stabilized before inspection, then the inspection can be performed quickly, but erroneous product determinations occur and measurement accuracy is reduced
Solution Approach 1:
The patent performs vacuum drying as a preliminary action before the electrical characteristic inspection. By removing residual organic substances through vacuum heating prior to inspection, the electrode condition is stabilized in advance, ensuring accurate sensitivity characteristics measurement while maintaining efficient inspection timing
3Reliability
If the sensor element is driven in a mixed gas atmosphere for pre-treatment, then the electrode condition improves, but the apparatus size and cost increase
Solution Approach 1:
The patent replaces the complex mixed gas atmosphere generation and control system with a simpler vacuum system. The vacuum drying apparatus requires only vacuum generation capability and heating function, eliminating the need for complex gas mixing, flow control, and atmosphere monitoring equipment, thus reducing apparatus size and cost while achieving the same electrode stabilization effect
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach stabilizes electrode conditions effectively, preventing erroneous product determinations and ensuring reliable sensitivity characteristics, thereby improving production yield and measurement accuracy of gas sensors.
Implementation Method 1
by an external power source, applying a voltage between the first electrode and the second electrode included in the element body having been subjected to the step e), to thereby decompose and remove an atmosphere gas of the step e) attached to the second electrode
Implementation Method 2
heating the element body having been subjected to the step d), in a reducing atmosphere
Data Source
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AI summary
To provide a method for manufacturing a sensor element, by which stabilization of an electrode, which is performed prior to inspecting element characteristics, can be performed for a shorter time period and in a more reliable manner than in the conventional. A pre-treatment prior to inspection of electrical characteristics is performed on a sensor element for use in a gas sensor that measures a concentration of a predetermined gas component in a measurement gas. The sensor element includes: an oxygen-ion conductive solid electrolyte layer; a first electrode that is formed on a surface of the oxygen-ion conductive solid electrolyte layer; and a second electrode that is formed in a space provided inside the oxygen-ion conductive solid electrolyte layer, and that is configured to reduce said predetermined gas component. As the pre-treatment, by an external power source, a voltage is applied between the first electrode and the second electrode, to thereby decompose and remove a gas component attached to the second electrode.