Wired Circuit Board Wire Alignment and Connection Reliability
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Solution Overview
Problem
Conventional methods for producing elongated flexible wired circuit boards for catheters face challenges in forming extra fine wires, leading to poor connection reliability and productivity due to misalignment of photomask patterns, resulting in disconnection or short circuits.
Innovation Solution
The design features a wired circuit board with parallel wires having linear and angled portions, where the connection portions are broader than the linear portions, with specific angle and length relationships to ensure secure linearity and reduce the need for precise angle adjustment, and a production method involving multiple light exposure steps with shifting photomasks to form these connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If photomask exposure is conducted multiple times to form elongated wires, then wire length can be increased beyond photomask size limits, but photomask opening end portions displace causing wire misalignment and connection reliability deterioration
Solution Approach 1:
The wire pattern is divided into multiple segments corresponding to multiple photomask exposure steps. Each photomask exposure forms a segment of the final wire pattern. By segmenting the overall wire formation into manageable exposure steps with overlapping regions, the patent enables formation of elongated wires exceeding photomask size limits while maintaining alignment through the overlap buffer zone.
Solution Approach 2:
The patent applies preliminary action by designing the photomask opening width to be greater than the target wire width, creating an overlapping region in advance. This preliminary excess width provides a buffer zone that compensates for potential displacement during multiple exposure steps. The overlap is built into the design before actual exposure occurs, ensuring alignment tolerance.
2Reliability
If photomask is disposed with high accuracy to eliminate wire dislocation, then connection reliability improves, but productivity decreases due to stringent positioning requirements
Solution Approach 1:
The patent applies preliminary action by designing the photomask opening width to be greater than the target wire width, creating an overlapping region in advance. This preliminary excess width provides a buffer zone that compensates for potential displacement during multiple exposure steps. The overlap is built into the design before actual exposure occurs, ensuring alignment tolerance.
Solution Approach 2:
The patent changes the parameter of photomask opening width to be larger than the final wire width. This parameter change creates an intentional overlap region that provides tolerance for positioning variations. By adjusting this dimensional parameter, the system achieves both reliability (through overlap compensation) and productivity (through relaxed positioning tolerances).
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 approach enhances connection reliability and productivity by ensuring secure connections and reducing the risk of short circuits, while allowing for longer wire lengths without compromising signal propagation.
Implementation Method 1
a photomask having an opening with a predetermined length and equal width at both end portions is disposed in a longitudinal direction of the insulating substrate so that the end portions of the opening overlap one after another and the resist layer is exposed to light repeatedly
Data Source
AI summary
An elongated wired circuit board including a plurality of wires arranged in parallel, wherein the plurality of wires each includes a first linear portion extending in a first linear direction, a second linear portion extending in a second linear direction, and a connection portion, the connection portion includes a first side, a second side, a third side, and a fourth side, length y1 and length S satisfy 0<y1<S, length y1 extending from the first corner portion reaching the first widthwise other end edge of the first linear portion, and length S extending from the first widthwise other end edge of the first linear portion of one wire, and the predetermined angle θ satisfies 0<θ<1 deg.