Thin-Film pH Half-Cell for High Integration Density
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Solution Overview
Problem
Existing pH measurement technologies, such as glass electrodes and ISFETs, face limitations in integration density, fragility, radiation sensitivity, material incompatibilities, and high temperature requirements, making them unsuitable for small-scale applications and biological processes.
Innovation Solution
A pH half-cell is produced by combining thin-film and thick-film processes, enabling the creation of small structure sizes with robustness and a wide range of materials, allowing for pH measurement and additional variable monitoring without integrated electronics, using a mixed-conducting glass and pH-sensitive glass layers applied via different deposition methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If glass electrodes are used for pH measurement, then measurement accuracy is improved, but integration density deteriorates due to large size
Solution Approach 1:
The patent combines multiple functions (pH measurement, temperature measurement, redox potential measurement) into a single integrated sensor device, achieving high integration density while maintaining measurement accuracy through the use of multiple miniaturized sensing elements on one substrate
Solution Approach 2:
The patent employs thin-film deposition techniques to create pH-sensitive membranes and other sensing layers with thicknesses in the nanometer to micrometer range, enabling miniaturization of the sensor while preserving the pH measurement function
2Measurement precision
If glass electrodes are used for pH measurement, then measurement accuracy is improved, but reliability deteriorates due to fragility
Solution Approach 1:
The patent replaces traditional thick glass electrodes with thin-film deposited membranes on rigid substrates, eliminating the fragility of glass while maintaining pH sensitivity through the thin-film swelling layer that forms on the deposited glass or glass-ceramic material
Solution Approach 2:
The patent uses composite structures combining substrate materials (ceramic, metal, or plastic) with thin-film deposited pH-sensitive layers, creating a hybrid sensor that gains mechanical strength from the substrate while retaining pH measurement capability from the thin film
3Area of moving object
If ISFET sensors are used for pH measurement, then miniaturization is improved, but adaptability deteriorates due to radiation sensitivity
Solution Approach 1:
The patent changes the material composition and structural parameters of the pH-sensitive layer, using materials like Ta2O5, SiN, Al2O3, or glass-ceramics that are resistant to radiation and can withstand sterilization processes, thereby maintaining miniaturization while improving adaptability to biological applications
4Ease of manufacture
If thick-film processes are used for sensor production, then manufacturing simplicity is improved, but manufacturing precision deteriorates due to shrinkage
Solution Approach 1:
The patent segments the manufacturing process into distinct stages: substrate preparation, thin-film deposition with controlled thickness, pattern formation, and sintering. This segmentation allows precise control of each step, particularly the thin-film deposition which determines the final structure accuracy independent of sintering shrinkage
Solution Approach 2:
The patent changes the deposition method from traditional thick-film screening to thin-film deposition techniques, enabling precise control of layer thickness in the nanometer to micrometer range. The thin-film layers are deposited with controlled thickness before sintering, and their final dimensions are determined by the deposition parameters rather than being solely dependent on sintering shrinkage
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 enhances integration density, reduces fragility, and allows for the measurement of multiple variables, including temperature and redox potential, while being compatible with various materials and processes, improving the robustness and versatility of pH measurement systems.
Implementation Method 1
If such a glass electrode is immersed in an aqueous solution, a swelling layer forms on the pH-sensitive membrane glass
Implementation Method 2
The pH half-cell is produced by combining thin-film processes and thick-film processes
Implementation Method 3
Common methods are sputtering, vapor deposition or chemical vapor deposition (CVD)
Data Source
Figure 1~2
Figure 3~5
AI summary
Method for producing a pH half-cell (1) by means of which, in combination with a reference electrode (2) and an evaluation electronics unit (3), a pH value (4) of a medium (5) can be determined, wherein the method for producing the pH half-cell (1) comprises the following steps: applying a first structure (8) and a second structure (9) onto a substrate (7), wherein the first structure (8) is applied by means of a thin-film method and forms a resistance element having a temperature-dependent resistance value, and wherein the second structure (9) can be employed to derive a pH-dependent potential (10); applying a structured passivation glass layer (11), wherein the passivation glass layer (11) substantially covers the first structure (8) and leaves the second structure (9) substantially uncovered; applying a mixed-conducting glass (12), wherein the mixed-conducting glass (12) is substantially applied to the region that was left uncovered by the passivation glass layer (11); applying a pH-sensitive glass (13), wherein the pH-sensitive glass (13) is applied on the mixed-conducting glass (12).