Flexible Board Impedance Control via Multi-Surface Ground Wiring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In electronic apparatuses, incorporating flexible boards with ground wires for impedance control is challenging due to increased thickness, which compromises flexibility and impedance matching, making it difficult to achieve both ease of integration and impedance control simultaneously.
Innovation Solution
The design features a structure with a bent and flat portion, utilizing two flexible boards where differential signal wires are on one board and ground wires for impedance control are on the other, with varying wiring densities between the bent and flat areas to maintain flexibility and achieve impedance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ground wires for impedance control are provided on one surface of the flexible board, then impedance control is achieved, but the thickness of the flexible board increases, causing loss of flexibility
Solution Approach 1:
The patent transitions from providing ground wires on a single surface (2D arrangement) to utilizing both surfaces of the flexible board (3D arrangement). By placing ground wires on the rear side of differential signal wires on the same flexible board and utilizing the opposite surface, the invention achieves impedance control without increasing single-surface wiring density, thereby maintaining flexibility while enabling proper impedance matching.
2Ease of operation
If no ground wires for impedance control are provided on the flexible board, then flexibility is maintained, but it becomes difficult to estimate parasitic components and achieve accurate impedance control
Solution Approach 1:
The patent combines the functions of signal transmission and impedance control into a single flexible board structure. By integrating ground wires for impedance control directly onto the flexible board (specifically on the rear side of differential signal wires), the invention merges the previously separate functions of maintaining flexibility and achieving impedance control, eliminating the need to choose between the two opposing requirements.
3Manufacturing precision
If ground wires are provided on the flexible board to achieve impedance control, then accurate impedance matching is possible, but the flexible board becomes difficult to incorporate into the electronic apparatus due to increased thickness
Solution Approach 1:
The patent segments the wiring arrangement into different surfaces of the flexible board, with differential signal wires on one surface and ground wires on the rear side. This segmentation allows the ground wires to be positioned without adding to the overall thickness of the flexible board, as they are distributed across different spatial layers (surfaces) rather than being stacked on the same plane, thereby facilitating easier incorporation into the electronic apparatus.
Data Source
AI summary
An electronic apparatus which achieves ease of incorporating flexible boards into the electronic apparatus and ease of impedance control at the same time. A first flexible board and a second flexible board are placed along a structure having a bent portion and a flat portion. Differential signal wires are wired on one surface of the first flexible board placed between the structure and the second flexible board, and first ground wires for impedance control of the differential signal wires are wired on the other surface and on a rear side of the differential signal wires. Second ground wires for impedance control of the differential signal wires are wired on one surface of the second flexible board the one surface of the first flexible board faces. A wiring density of the first and second ground wires differs between an area along the bent portion and an area along the flat portion.