Microfluidic Sensor Assembly With Intermediate Layer for CTE Mismatch
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Solution Overview
Problem
Existing fluid control and measurement devices face challenges in withstanding a wide range of temperatures and pressures, are prone to chemical degradation, and require improved packaging to separate electrical and fluidic connections, while minimizing sensor damage from pressure and temperature.
Innovation Solution
A device comprising a base part and microfabricated part separated by an intermediate layer with pliant attachment layers that absorb thermal expansion and pressure differences, using materials with different coefficients of thermal expansion (CTE) and a stiff intermediate layer to compensate for these variations, allowing separate electrical and fluidic connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the base part and microfabricated part are made of materials with different CTEs to improve adaptability, then the device can withstand a wider range of temperatures and pressures, but the assembly becomes more complex due to the need for intermediate layers and pliant attachment means
Solution Approach 1:
An intermediate layer is introduced between the base part and microfabricated part to bridge materials with different CTEs. This intermediate layer acts as a mediator that accommodates thermal expansion differences while maintaining a reliable connection, enabling the assembly to withstand wider temperature ranges without direct bonding of incompatible materials.
Solution Approach 2:
Pliant attachment layers are used to connect the base part, intermediate layer, and microfabricated part. These flexible thin films can deform elastically to absorb CTE mismatches and mechanical stress, providing a compliant connection that maintains integrity under thermal and pressure cycling while simplifying the overall assembly process.
2Device complexity
If the microfabricated part is directly attached to the base part to reduce device complexity, then the assembly is simpler, but the sensor becomes sensitive to damage from pressure and temperature variations
Solution Approach 1:
The pliant attachment layers are designed beforehand to cushion and absorb mechanical stress and thermal expansion forces before they can reach the sensitive microfabricated part. This pre-cushioning approach protects the sensor from damage during assembly and operation under varying pressure and temperature conditions.
Solution Approach 2:
The flexible pliant attachment layers serve as protective films that decouple the rigid base part from the fragile microfabricated part. These compliant layers absorb stress concentrations and prevent direct transmission of pressure and thermal shocks to the sensor, thereby improving reliability without requiring complex protective housings.
3Device complexity
If electrical connections and fluidic connections are integrated in the same structure to reduce device complexity, then the assembly is more compact, but fluid leakages can damage electrical connections
Solution Approach 1:
The connection structure is segmented into separate fluidic pathways and electrical connection zones. The flow channels are routed through the base part and intermediate layer to reach the microfabricated part's fluid ports, while electrical connections are established through separate bonding wires or traces on the microfabricated part's backside, physically isolating electrical components from fluid exposure.
Solution Approach 2:
Electrical and fluidic connections are separated in the vertical dimension. Fluid connections are made through the thickness of the base part and intermediate layer to the front surface of the microfabricated part, while electrical connections are made to the back surface, utilizing the third dimension to achieve spatial separation and prevent fluid access to electrical components.
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
The device achieves higher pressure tolerance, improved accuracy, and stability under extreme conditions, eliminating the need for a separate PCB and reducing sensor damage, while maintaining leak-tightness and chemical resistance.
Implementation Method 1
the first attachment means and/or the second attachment means comprise a first and/or a second pliant attachment layer
Implementation Method 2
the base part and the microfabricated part being made of materials having different coefficients of thermal expansion (CTE's)
Implementation Method 3
the intermediate layer having a CTE between a CTE of the base part and a CTE of the microfabricated part
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a device (1) for controlling or measuring a fluid, comprising: - a base part (2); - a microfabricated part (3) for measuring, controlling or regulating a fluid; - an inlet flow channel (4), extending from a flow inlet (34) in the base part to a flow inlet (5) of the microfabricated part; and - an outlet flow channel (6), extending from a flow outlet (7) of the microfabricated part to a flow outlet (35) in the base part, characterized in that - the base part (2) and the microfabricated part (3) are separated by an intermediate layer (8), wherein the intermediate layer is attached to the base part via a first attachment means (11) and attached to the microfabricated part via a second attachment means (12).