Rigid-Flex Sensor Interconnect for Signal Integrity and Thermal Isolation
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Solution Overview
Problem
High-speed sensor modules face challenges in maintaining signal integrity and thermal isolation while operating at high data rates and extreme temperatures, particularly in vacuum environments, due to the delicate design trade-offs between connection density and thermal performance.
Innovation Solution
A rigid-flex assembly is introduced, comprising a flexible wiring section with controlled separation gaps between opposing flexible strips and rigid substrates, which facilitates high-speed data transfer while minimizing thermal conductivity and maintaining signal integrity, and is coupled to a connector for attachment to a computer system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper wires and connectors are used for data transfer, then signal transmission is achieved, but thermal conductivity increases causing thermal loads on the sensor module
Solution Approach 1:
The patent extracts the thermal conduction path by removing continuous copper wires and replacing them with flexible printed circuit boards that have interrupted ground planes and controlled impedance traces. This eliminates the direct thermal pathway while preserving electrical connectivity through the flexible circuit's signal traces.
Solution Approach 2:
The patent changes the thermal and electrical parameters of the connection medium by transitioning from solid copper wires to flexible PCB traces with controlled impedance. The flexible PCB's dielectric material and trace geometry are optimized to provide electrical conductivity while minimizing thermal conductivity, achieving parameter optimization for both signal integrity and thermal isolation.
2Reliability
If flexible wiring with continuous copper traces is used, then electrical connectivity is maintained, but signal integrity degrades at high data rates due to impedance control issues
Solution Approach 1:
The patent implements controlled impedance by precisely controlling the trace geometry, dielectric thickness, and material properties of the flexible PCB. The trace width, spacing, and distance from ground planes are optimized to maintain characteristic impedance matching for high-speed signals, ensuring signal integrity at 2.7 Gbps and above.
Solution Approach 2:
The patent replaces traditional wire-wrap or rigid PCB connections with a flexible PCB system that uses printed traces instead of mechanical wire connections. This substitution enables precise control of electrical parameters through photolithographic manufacturing while maintaining flexibility for thermal isolation.
3Stability of the object's composition
If rigid substrates are used for stable connections, then structural stability is achieved, but thermal isolation is reduced due to increased contact area
Solution Approach 1:
The patent segments the rigid substrate structure into multiple thin layers separated by dielectric materials and air gaps. The flexible PCB is constructed with multiple laminated layers creating a stacked configuration that provides structural stability through distributed support while minimizing thermal conduction paths through the dielectric barriers between layers.
4Temperature
If vacuum environment is used for thermal isolation, then thermal performance improves, but manufacturing complexity increases due to vacuum sealing requirements
Solution Approach 1:
The patent uses flexible PCB materials with inherent dielectric properties that provide thermal isolation without requiring vacuum sealing. The flexible circuit board's polyimide or similar dielectric layers act as thermal barriers, achieving thermal performance comparable to vacuum environments while maintaining atmospheric pressure operation and simplifying manufacturing.
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 configuration enables high-speed data transfer up to 2.7 Gbps with optimal signal integrity and reduced thermal loads, allowing the sensor module to operate effectively at temperatures below 40 Kelvins over hundreds of thermal cycles, meeting stringent requirements for continuous operation in vacuum conditions.
Implementation Method 1
a controlled separation gap defined by a distance between the first flexible strip and the second flexible strip to provide a low thermal conductive path while maintaining signal integrity
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A rigid-flex assembly (RFA) includes a circuit board (12) attachable to a focal plane sensor (14). The RFA includes a flexible wiring section (18) electrically coupled at opposing ends to the circuit board and to an edge connector (22). The flexible wiring section has a controlled separation distance or volume or vacuum gap between wiring strips for reduction of dielectric electrical loss and electrical cross talk. The flexible section has wires or traces configured to reduce the amount of copper used while optimizing signal integrity. Rigid substrates electrically couple the flexible wiring section to the connector. The RFA uses an end-launch, in-plane connection to the sensor for improved performance. A sensor module includes a housing and a sensor. An RFA is coupled to the sensor for high-speed data transfer and that optimizes signal integrity while providing thermal isolation via the flexible section.