Printed Wiring Board Non-Conductive Area Terminal Protection

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Solution Overview

Problem

The existing printed wiring boards face issues with terminal bending causing damage to the conductive pattern, leading to potential electrical shorts due to the terminal's tip contacting adjacent conductive areas, especially when the terminal is bent away from its intended direction or protrudes outside the land.

Innovation Solution

A printed wiring board design featuring a non-conductive area formed in a fan-shaped shape around the through-hole, which prevents contact between the terminal and the conductive pattern, ensuring the terminal remains positioned within this area even when bent, thus avoiding damage and shorts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the terminal is bent to mount the electric component on the printed wiring board, then the electric component can be temporarily fixed and soldered, but the tip of the terminal may damage the conductive pattern or cause short circuit

Engineering Contradiction:
Improveease of component mountingVSAvoidrisk of conductive pattern damage
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces a non-conductive area as an intermediary zone between the terminal and the conductive pattern. This mediator prevents direct contact between the terminal tip and the conductive pattern during the bending and soldering process, thereby protecting the conductive pattern from damage while still allowing the terminal to be bent for component mounting.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The non-conductive area is pre-formed around the through-hole before the terminal is inserted and bent. This preliminary preparation creates a safe zone that guides the terminal bending process and prevents damage to the conductive pattern from the outset, rather than requiring corrective measures after damage occurs.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the land is formed into a teardrop shape to guide terminal bending, then the terminal direction is limited, but the terminal may still protrude from the land due to production accuracy or assembly looseness

Engineering Contradiction:
Improveterminal positioning accuracyVSAvoidterminal protrusion risk
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The non-conductive area serves as a cushioning zone that accommodates variations in terminal positioning. Even if the terminal protrudes from the land due to production accuracy issues or assembly looseness, the non-conductive area provides a buffer that prevents the terminal tip from reaching and damaging the conductive pattern, thereby cushioning against potential failures.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent applies different properties to different areas: the land area provides precise positioning and electrical connection, while the non-conductive area provides protection and accommodation for positioning variations. This local differentiation of functional qualities allows the system to simultaneously achieve precise positioning and tolerance for manufacturing variations.

Inventive Principle:
Principle #3Local quality

3Reliability

If the non-conductive area is expanded to fully protect the conductive pattern, then terminal damage is prevented, but the design flexibility and space utilization are reduced

Engineering Contradiction:
Improveconductive pattern protectionVSAvoiddesign constraint
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The non-conductive area is designed to provide just enough protection to prevent terminal damage to the conductive pattern, rather than completely enclosing the through-hole. This partial action approach provides sufficient reliability while minimizing design constraints and maintaining space utilization efficiency.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP1983809B1Printed wiring board
Publication Date: 2018.09.12 YAZAKI CORP
  • EP1983809B1 patent drawingFigure 1
  • EP1983809B1 patent drawingFigure 2
  • EP1983809B1 patent drawingFigure 3

AI summary

The present invention is to provide a printed wiring board which can certainly prevent damage of conductive pattern caused by the terminal. The printed wiring board has a board, a conductive pattern, a through-hole and a non-conductive area. A lead wire of resistance mounted on the printed wiring board is inserted into the through-hole 4. The lead wire projects from a surface of the board, and is bent close to the surface. The non-conductive area is formed into a fan-shaped shape enlarging toward a tip of the lead wire from a center of the through-hole. Since the bent lead wire is arranged on the non-conductive area, the non-conductive area can prevent damage of the conductive pattern which is caused by touching the lead wire to the conductive pattern.