Foldable FPCB Sealer Structure for Moisture Blocking

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Solution Overview

Problem

Existing electronic devices face challenges in maintaining moisture resistance and structural integrity, particularly in foldable designs with flexible circuit boards, as they are prone to moisture penetration and require effective sealing solutions.

Innovation Solution

A foldable electronic device incorporates a flexible circuit board with varying thickness portions and a sealer system, including sealing portions with different thicknesses and moduli to prevent moisture ingress, supported by a deformable housing and internal support members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible circuit board with varying thickness is used in foldable devices, then structural adaptability and signal transmission are improved, but moisture penetration risk increases due to gaps and uneven surfaces

Engineering Contradiction:
Improvestructural adaptabilityVSAvoidmoisture penetration
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The sealer is designed with varying thickness to match the varying thickness of the flexible circuit board. The first sealing portion has a first thickness corresponding to the first portion of the circuit board, while the second sealing portion has a second thickness corresponding to the second portion. This local adaptation ensures complete coverage and sealing at all locations, preventing moisture penetration while maintaining structural adaptability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sealer acts as an intermediary component between the flexible circuit board and the housing. It fills the gap created by the varying thickness of the circuit board and provides a continuous sealing barrier, mediating between the non-uniform circuit board surface and the uniform housing interior to prevent moisture ingress.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If sealers with different thicknesses are used to match varying circuit board portions, then sealing effectiveness is improved, but device complexity increases

Engineering Contradiction:
Improvesealing effectivenessVSAvoidsealer structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealer is segmented into multiple sealing portions (first sealing portion and second sealing portion) with different thicknesses. Each sealing portion is positioned to correspond to a specific portion of the flexible circuit board. This segmentation allows the sealer to adapt to varying circuit board thickness while maintaining a relatively simple overall structure that can be manufactured as a single integrated component.

Inventive Principle:
Principle #1Segmentation

3Volume of moving object

If the flexible circuit board is made thinner for miniaturization, then device portability is improved, but structural integrity and moisture resistance deteriorate

Engineering Contradiction:
Improvedevice sizeVSAvoidstructural integrity
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent utilizes a flexible circuit board with varying thickness, where thinner regions provide miniaturization and portability, while the sealer (acting as a protective film or shell) compensates for the reduced structural integrity. The sealer provides the necessary protection and structural support where the thin circuit board portions are most vulnerable to moisture and mechanical stress.

Inventive Principle:
Principle #30Flexible shells and thin films

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

The solution enhances moisture resistance and structural integrity in foldable devices by effectively sealing the flexible circuit board, ensuring reliable operation and durability.

Implementation Method 1

a sealer engaged between the flexible circuit board and a portion of a support member inside the first housing and configured to prevent moisture from penetrating into the first housing

Methodology Applied
Scientific EffectPhysical barrier sealing:

Implementation Method 2

a flexible circuit board extending across the hinge in a first direction to be connected to first circuitry in the first housing and second circuitry in the second housing, and including a first portion having at least one signal line and a second portion having at least one signal line

Methodology Applied
Scientific EffectElectrical signal transmission: Conduction (electrical)

Data Source

PatentEP4697871A1Electronic device including sealer
Publication Date: 2026.02.18 SAMSUNG ELECTRONICS CO LTD
  • EP4697871A1 patent drawingFigure 1
  • EP4697871A1 patent drawingFigure 2
  • EP4697871A1 patent drawingFigure 3

AI summary

The disclosure relates to an electronic device. A foldable electronic device according to an embodiment of the disclosure may include a foldable housing including a first housing and a second housing, a hinge rotatably coupling the first housing and the second housing, a flexible circuit board extending across the hinge in a first direction to be connected to first circuitry in the first housing and second circuitry in the second housing, and including a first portion having at least one signal line and a second portion having at least one signal line, and a sealer engaged between the flexible circuit board and a support in the first housing and configured to block penetration of moisture into an interior of the first housing. The first and second portions of the flexible circuit board may be disposed side by side in a second direction perpendicular to the first direction, wherein the second portion has a second thickness smaller than a first thickness of the first portion or is configured to be compressible to a second thickness smaller than the first thickness. The sealer may have a first sealing portion that presses the first portion of the flexible circuit board and a second sealing portion that presses the second portion of the flexible circuit board. The second sealing portion may have a thickness greater than that of the first sealing portion.