Soldered Sealing Connection for Sensor Substrate
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Solution Overview
Problem
Existing sensor systems face challenges in automotive applications where they must monitor various measurands like pressure and gas concentrations in aggressive and humid environments, requiring protection for electronic components while allowing medium access, and existing assembly methods lack efficiency and reliability.
Innovation Solution
A sensor system using solderable metal alloys for sealing sensitive areas, where the sealing is integrated with the electrical connection between the sensor substrate and circuit carrier, employing reflow soldering technology to form a gas-tight interface, thereby preventing ingress of aggressive media.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate sealing and electrical connection steps are used, then sealing reliability can be improved, but assembly complexity and time increase
Solution Approach 1:
The patent combines sealing and electrical connection functions into a single integrated solder joint. The solder serves dual purposes: establishing electrical connectivity between the sensor substrate and circuit carrier while simultaneously creating a hermetic seal around the media channel opening. This eliminates the need for separate sealing steps and reduces assembly complexity.
Solution Approach 2:
The solder material performs multiple functions simultaneously: it provides electrical conductivity for signal transmission, creates a mechanical bond between substrates, and forms a hermetic seal to protect against aggressive media. This multi-functionality resolves the contradiction by achieving reliable sealing without additional assembly steps.
2Manufacturing precision
If complex multi-step assembly processes are used, then sealing quality can be improved, but productivity decreases
Solution Approach 1:
The patent merges multiple assembly operations (sealing, electrical connection, mechanical bonding) into a single soldering step. This standard reflow soldering process achieves high sealing quality through proper solder material selection and process control while maintaining high productivity typical of automated SMT lines.
Solution Approach 2:
The patent optimizes solder material parameters (composition, melting point, wetting properties) to achieve both high sealing quality and efficient processing. By selecting appropriate solder alloys and controlling reflow temperature profiles, the process achieves hermetic seals while maintaining fast cycle times for high-volume production.
3Productivity
If automated assembly processes are used, then productivity increases, but sealing reliability may decrease due to precision requirements
Solution Approach 1:
The patent segments the sealing function into distinct geometric features (sealing profile, sealing land, media channel positioning) that can be independently optimized. This segmentation allows automated pick-and-place machines to position components with standard tolerances while the solder material compensates for minor misalignments to ensure hermetic sealing.
Solution Approach 2:
The solder material acts as an intermediary that compensates for positioning tolerances in automated assembly. Its fluid state during reflow allows it to flow into and seal around the media channel opening even with minor misalignments, while the automated process ensures consistent material application and heating for reliable sealing.
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 effectively seals the interface between the sensor substrate and circuit carrier, protecting electronic components from humidity and chemicals, while allowing medium access, and simplifies the assembly process by combining sealing and electrical connection in a single step.
Implementation Method 1
The first and second sealing patterns are arranged in the circuit carrier and sensor substrate, respectively, so as to be aligned with respect to the media channel, when the sensor arrangement is mounted onto the circuit carrier, and have respective shapes and sizes adapted to form a soldered sealing connection, which surrounds said media channel, between the first sealing pattern and the second sealing pattern
Implementation Method 2
a soldered sealing connection, which surrounds said media channel, between the first sealing pattern and the second sealing pattern and which seals, around the media channel, an interface between the circuit carrier and the sensor substrate against the ingress of aggressive media into said interface and towards the at least one contact pad and the at least one terminal of the sensor arrangement
Data Source
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AI summary
The present invention relates to a sensor arrangement, to a corresponding method of assembling such a sensor arrangement, and to a sensor system. The sensor arrangement comprises at least one transducer element (106, 106', 106"; 206; 306; 406) for monitoring at least one measurand and generating an electrical output signal correlated with the at least one measurand; and a sensor substrate (112; 312; 406) comprising said transducer element. The sensor substrate (112; 312; 406) is mountable on a circuit carrier (104; 204; 304; 404) in a way that a media channel (124) penetrating the circuit carrier allows access of the at least one measurand to the transducer element. The circuit carrier has an electrically conductive solderable first sealing pattern (132; 432) which surrounds said media channel at least partly and which is aligned with a solderable second sealing pattern (134; 434) arranged on the sensor substrate, so that a soldered sealing connection, which at least partly surrounds said media channel, is formed between the first sealing pattern and the second sealing pattern.