Thick Film Sensor Electrodes Composite Material Precision
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Solution Overview
Problem
Existing sensors with electrodes made of composite oxide and platinum are not resistant to aggressive media and have frayed border regions, limiting their accuracy and applicability, especially in thin-film or resinate technology.
Innovation Solution
The development of sensors with electrodes formed from a composite of metal and inorganic oxide, specifically platinum group metals and glass or ceramic, with precise film thickness and spacing to reduce border fraying, enabling accurate and resistant structures suitable for aggressive environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thick-film technology is used to produce electrodes, then the electrodes are resistant to aggressive media, but the measurement precision is reduced compared to thin-film technology
Solution Approach 1:
The patent employs composite electrodes made of platinum group metals combined with inorganic oxide (such as aluminum oxide or silicon oxide) to create a material that integrates both the chemical resistance of thick-film technology and the measurement precision of thin-film technology. The composite structure allows the electrode to maintain fine trace dimensions (5-70 μm) while exhibiting superior resistance to aggressive media.
2Length of moving object
If conductor traces with thickness less than 20 μm are produced by screen printing, then the trace width can be reduced, but the border region frays more significantly
Solution Approach 1:
The patent fundamentally changes the material parameters of the conductor trace by using composite materials (platinum group metal combined with inorganic oxide) instead of conventional screen printing paste. This material parameter change enables the trace to maintain its geometric integrity at widths of 5-70 μm without significant border fraying, even at reduced thicknesses of 0.5-20 μm.
3Measurement precision
If thin-film or resinate technology is used to produce finer electrode structures, then the measurement precision is improved, but the electrodes are not resistant to aggressive media
Solution Approach 1:
The patent creates a composite material system where platinum group metals provide the necessary electrical conductivity and fine-structure capability for high measurement precision, while the inorganic oxide component (such as aluminum oxide or silicon oxide) provides the chemical resistance required for aggressive media environments. This composite approach enables simultaneous achievement of both precision and reliability.
Data Source
AI summary
A sensor, particularly an impedance sensor, for example a soot sensor, is provided which has two mutually electrically insulated electrodes, wherein at least one external electrode is formed from a composite of metal and inorganic oxide as a film pattern having a film thickness of 0.5 to 20 μm. The trace width of the film pattern and the spacing between the traces is 5 to 70 μm and the border region around the conductor trace edge varies less than 10 μm. Both electrodes can be arranged adjacent to each other as a film pattern in a plane. Preferably, the sensor has a heater. For mass production, electrodes are produced as a film pattern having a film thickness of 0.5 to 20 μm on electrically insulating oxide bases and, following full-surface imprinting of a metal powder and oxide-containing paste, the electrodes are structured particularly accurately as traces from the printed film. In particular, the film thickness of the printed film is reduced.