Flexible Wiring Board Layout for Foldable Light Control Sheets

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Solution Overview

Problem

Existing light control sheets with transparent electrode layers facing each other lack efficient and flexible bonding methods for flexible wiring boards, limiting their integration and functionality.

Innovation Solution

A flexible wiring board with insulating and conductive layers, featuring point-symmetric adhesive terminals and weakened parts for folding, is bonded to a light control sheet with exposed transparent electrode terminals, allowing for double-sided attachment and reduced folding resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible wiring board is bonded to a light control sheet, then integration and functionality are enhanced, but folding resistance and bonding complexity increase

Engineering Contradiction:

Improveintegration functionalityVSAvoidbonding complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The flexible wiring board is divided into multiple bonding regions with different adhesive terminal configurations. Some regions have adhesive terminals for bonding to the light control sheet, while other regions are designed as bonding-free zones to maintain flexibility and reduce folding resistance. This segmentation allows the board to be bonded where needed while remaining flexible where required.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the flexible wiring board are assigned different properties: regions requiring strong bonding have adhesive terminals with higher adhesive area ratios, while regions requiring flexibility have reduced or no adhesive terminals. This local differentiation optimizes both bonding strength and folding performance in different areas of the same board.

Inventive Principle:

Principle #3Local quality

2Strength

If adhesive terminals are added to the flexible wiring board, then bonding strength increases, but folding flexibility decreases

Engineering Contradiction:

Improvebonding strengthVSAvoidfolding flexibility

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

Adhesive terminals are applied partially rather than uniformly across the entire flexible wiring board. The adhesive terminals are concentrated in specific regions where bonding is required, while other regions remain free of adhesive terminals to maintain folding flexibility. This partial application achieves sufficient bonding strength without compromising overall flexibility.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The adhesive area ratio of the adhesive terminals is optimized to balance bonding strength and folding flexibility. By controlling the proportion of adhesive material and its distribution, the board achieves adequate bonding in critical areas while maintaining sufficient flexibility for folding applications. The adhesive terminal dimensions and spacing are adjusted to achieve the optimal parameter balance.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS12593398B2Flexible wiring board and light control unit

Publication Date: 2026.03.31 TOPPAN INC

AI summary

A flexible wiring board includes an insulating layer having a support surface extending in a first direction; a first sheet adhesive terminal positioned on the support surface; and a second sheet adhesive terminal positioned on the support surface. The shape of the first sheet adhesive terminal and the shape of the second sheet adhesive terminal are point-symmetric about a point on a straight fold line on which straight guide lines extending in the first direction lie.