Sensor Assembly Metallization Sealing Fluid Path
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Solution Overview
Problem
Existing sensor chip arrangements face conflicts between achieving short response times and preventing fluid contamination, as housing materials can slow response times and contaminate the fluid being measured.
Innovation Solution
A sensor assembly with a substrate arrangement that includes a metallization layer to seal the access path for the fluid, minimizing contamination and absorption, and an encapsulation that protects the sensor chip without covering the sensing element, allowing for a short and contamination-free measurement path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the sensor chip is exposed directly to the environment, then the response time is shortened, but the mechanical protection is reduced
Solution Approach 1:
The housing is divided into two separate parts: a rigid housing body providing mechanical protection and a flexible membrane providing fluid access. This segmentation allows each part to fulfill its specific function optimally - the rigid housing protects the sensor chip while the flexible membrane enables direct fluid contact with minimal response time.
Solution Approach 2:
A flexible membrane is used as the access path to the sensing element. This thin film structure allows the fluid to reach the sensor chip directly while maintaining mechanical integrity, thus achieving both short response time and adequate protection.
2Strength
If a housing is used to protect the sensor chip, then the mechanical protection is improved, but the response time increases due to fluid traveling through the housing
Solution Approach 1:
The housing is segmented into a protective rigid body and a thin flexible membrane access path. This allows the fluid to travel through minimal material (the membrane) rather than a full housing structure, significantly reducing response time while maintaining protection.
Solution Approach 2:
The use of a thin flexible membrane as the access path minimizes the distance and material the fluid must traverse, thereby reducing response time while still providing the necessary mechanical protection and sealing.
3Ease of manufacture
If a rubber cap is used for protection, then the assembly tolerance requirements are reduced, but the response time increases drastically
Solution Approach 1:
The flexible membrane is designed as an extremely thin film structure that provides both the necessary sealing function and minimal resistance to fluid flow. This thin film approach achieves easy assembly like rubber caps while avoiding their thick-material response time penalty.
4Strength
If housing materials such as hard plastics or rubber are used, then the mechanical protection is provided, but the fluid contamination occurs through outgassing and absorption
Solution Approach 1:
The flexible membrane is designed as an extremely thin film that minimizes the volume of material in direct contact with the fluid. This reduces the amount of material available for outgassing and absorption, thereby minimizing fluid contamination while still providing necessary protection and sealing functionality.
Data Source
AI summary
A sensor assembly comprises a substrate arrangement and a sensor chip mounted to the substrate arrangement. A sensing element is integrated on or in the sensor chip and is sensitive to at least one parameter of a fluid. An access opening is provided in the substrate arrangement enabling the fluid to access the sensing element. A metallization arranged on at least a portion of the substrate arrangement seals a chamber containing the sensor chip which portion comprises one or more of a wall defining the access opening or an area facing the sensor chip.