Variable-Thickness Insulation in Wiring Circuit Boards for Impedance Matching
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Solution Overview
Problem
Conventional wiring circuit boards face challenges in adjusting impedance between terminals and wires, particularly when the terminal is small or the metal supporting board is thick, making it difficult to form openings in the metal layer.
Innovation Solution
The wiring circuit board design includes a configuration where the terminal width is larger than the connecting portion, with a distance between the terminal and the metal layer being longer than the distance between the connecting portion and the metal layer, achieved through varying thicknesses of the insulating layer and potentially incorporating a concave portion or multiple metal layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an opening portion is formed in the metal supporting board to adjust characteristic impedance, then impedance matching between terminal and wire is improved, but manufacturing difficulty increases when terminal is small or metal board is thick
Solution Approach 1:
The patent transitions from adjusting impedance by modifying the metal layer (horizontal dimension) to adjusting impedance by varying insulating layer thickness (vertical dimension). The insulating layer thickness is made greater under the terminal than under the wire, thereby increasing impedance under the terminal to match the wire's impedance without requiring openings in the metal layer.
Solution Approach 2:
The patent changes the physical parameter of insulating layer thickness to control impedance characteristics. By making the insulating layer thickness variable (thicker under terminal, thinner under wire), the impedance is adjusted to achieve matching between terminal and wire without mechanical modifications to the metal layer.
2Strength
If the metal supporting board is made thick to provide structural support, then mechanical strength is improved, but impedance adjustment becomes difficult
Solution Approach 1:
The patent decouples the functions of mechanical support and impedance adjustment by using different layers: the thick metal layer provides mechanical strength, while the variable-thickness insulating layer handles impedance adjustment. This allows both requirements to be satisfied simultaneously without compromise.
Solution Approach 2:
The patent uses insulating layer thickness as the control parameter for impedance adjustment, independent of metal layer thickness. This allows the metal layer to be made thick for structural support while impedance is precisely controlled through insulating layer variations.
Data Source
AI summary
A wiring circuit board includes a metal layer, a base insulating layer, and a circuit pattern. The circuit pattern includes a terminal and a wire connected to the terminal. The wire has a connecting portion connected to the terminal. The width of the terminal is larger than the width of the connecting portion. In the thickness direction, a distance between at least a portion of the terminal and the metal layer is longer than a distance between at least a portion of the connecting portion and the metal layer.