Vehicular Camera Stacked PCB Grounding for EMI Reduction
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Solution Overview
Problem
Existing vehicle vision systems face challenges with high-speed digital data transmission due to electromagnetic interference (EMI) and require intricate and costly machining for coaxial connections, limiting design flexibility and increasing costs.
Innovation Solution
A vehicle vision system with enhanced electrical connections using a coaxial connector and printed circuit board (PCB) that incorporates a ground clamp and conductive shield for improved grounding, reducing EMI and enhancing data transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shielded coaxial cable is used for high speed digital data transmission, then electromagnetic interference isolation is improved, but device complexity and manufacturing cost increase due to intricate machining requirements
Solution Approach 1:
The patent replaces the traditional mechanical coaxial connector assembly (requiring intricate machining, casting, or stamping operations) with a PCB-integrated coaxial interface. The coaxial signal path is directly formed on the PCB through controlled impedance traces and ground planes, eliminating the need for separate mechanical connectors while maintaining EMI shielding effectiveness.
Solution Approach 2:
The patent merges the coaxial connector function directly into the PCB structure. The signal transmission path, ground reference, and shielding are integrated into a single PCB layer structure, combining multiple functions (signal transmission, grounding, EMI protection) that were previously separated into distinct mechanical components.
2Reliability
If intricate machining operations are used for coaxial connections, then connection reliability is improved, but manufacturing cost and production time increase
Solution Approach 1:
The patent replaces complex mechanical machining operations with standard PCB fabrication processes. The coaxial interface is created using conventional PCB techniques (copper trace deposition, plating, and lamination) rather than requiring precision machining, casting, or stamping operations, significantly simplifying manufacturing while maintaining connection reliability.
Solution Approach 2:
The patent changes the manufacturing approach from mechanical dimensional control to electrical parameter control. Instead of relying on mechanical tolerances from machining operations, the design uses PCB-controlled impedance parameters and electrical ground plane configurations to ensure reliable high-speed signal transmission.
3Reliability
If traditional coaxial connectors are used, then electrical connection is achieved, but design flexibility is reduced due to fixed connector geometries
Solution Approach 1:
The patent segments the coaxial interface into multiple PCB layers, allowing the signal path to be routed flexibly through different layers while maintaining controlled impedance. This layered approach enables the same electrical connection function to be adapted to various board layouts and connector positions without requiring changes to the fundamental connection reliability.
Solution Approach 2:
The patent moves the coaxial interface design from a two-dimensional mechanical connector problem to a three-dimensional PCB layer problem. By utilizing multiple PCB layers and vertical via connections, the design achieves flexible routing and positioning capabilities that are not constrained by the fixed geometries of traditional mechanical connectors.
Data Source
AI summary
A vehicular camera includes a front housing portion, a first circuit board having an imager, a second circuit board in board-to-board electrical connection with the first circuit board, and a rear housing portion having a connector for electrically connecting to an electrical connection of a wire harness of a vehicle. The rear housing portion when joined with the front housing portion forms a camera housing. The connector of the rear housing portion includes a multi-pin connector having at least three terminals that, with the rear housing portion joined with the front housing portion, electrically connect to respective terminals of the electrical connector at the second circuit board. The connector includes an electrically conductive metallic clamping element that engages a metallic shield element at the electrical connector at the second circuit board to establish a ground path from the connector of the rear housing portion to the second circuit board.