Flexible Printed Circuit Board Rupture Prevention Design

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Solution Overview

Problem

Flexible printed circuit boards in portable electronic devices, such as LCD modules, are prone to rupture due to folding stresses, especially at the junctions with glass substrates, leading to operational failures.

Innovation Solution

A flexible printed circuit board design featuring a single-layered flexible substrate surrounded by an insulating layer with strategically placed openings to prevent rupture, maintaining flexibility and strength by shielding edges and corners from damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the flexible printed circuit board is made thinner to reduce thickness, then the slimness requirement is satisfied, but the board becomes more prone to rupture due to folding stresses

Engineering Contradiction:

Improvethickness of flexible printed circuit boardVSAvoidresistance to rupture

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The patent applies composite materials by combining the flexible substrate with an insulating layer to form a multi-layer composite structure. This composite construction enhances the mechanical strength and rupture resistance of the thin flexible circuit board without significantly increasing its overall thickness, thereby resolving the contradiction between thinness and strength.

Inventive Principle:

Principle #40Composite materials

2Volume of moving object

If the flexible printed circuit board is folded to fit internal space, then the space requirement is satisfied, but rupture occurs at the junction between the flexible board and glass substrate

Engineering Contradiction:

Improveinternal space utilizationVSAvoidoperational reliability

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The insulating layer acts as a protective cushioning layer that is applied beforehand to the flexible substrate. This layer provides mechanical protection and stress distribution at critical locations such as the junction between the flexible board and glass substrate, preventing rupture during folding operations and ensuring reliable operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If the flexible printed circuit board is folded during assembly or use, then the flexibility requirement is satisfied, but the board may be cut off by the glass edge or ruptured due to flexing force

Engineering Contradiction:

ImproveflexibilityVSAvoidresistance to cutting and rupture

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The patent employs the flexible substrate as a flexible shell structure that can be folded and adapted to various configurations. The insulating layer reinforces this flexible structure, providing protection against cutting by glass edges and rupture due to flexing forces, thereby maintaining both flexibility and strength.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS8367936B2Flexible printed circuit board and method for forming monitor

Publication Date: 2013.02.05 RED OAK INNOVATIONS LTD

AI summary

The disclosure relates to a flexible printed circuit board and a method for manufacturing a monitor. The flexible printed circuit board is disposed on a portion of an upper surface of a substrate and is folded to a sidewall and a lower surface of the substrate. The flexible printed circuit board includes a flexible substrate and an insulating layer surrounding the flexible substrate. The insulating layer has an opening at least exposing a portion of the flexible substrate situated relative to the sidewall of the substrate.