Flexible Display Bonding Structure for Uniform Conductive Particle Dispersion

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Solution Overview

Problem

Existing display technologies face challenges in ensuring reliable and stable electrical connections between flexible circuit boards and silicon-based OLEDs, particularly in VR/AR devices, due to issues with conductive particle dispersion and structural integrity during bonding processes.

Innovation Solution

A display assembly design featuring a flexible circuit board with a wave-shaped first edge and reinforcement plates to disperse conductive particles uniformly and enhance structural stability, using anisotropic conductive adhesive for electrical connection and reinforcement layers to prevent oxidation and structural damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flexible circuit board is connected to a silicon-based OLED using a conventional bonding structure with flat edges, then the assembly process is simple, but the conductive particles are not uniformly dispersed and the electrical connection reliability is poor

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidbonding structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bonding structure employs a wave-shaped first edge with alternating convex and concave portions instead of a flat edge. This curvature design causes conductive particles to disperse uniformly along the wave pattern during bonding, improving electrical connection reliability while maintaining reasonable structural complexity

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the bonding structure by creating convex portions with specific arc lengths and concave portions with controlled depths. These parameter variations optimize the dispersion of conductive particles and enhance the bonding reliability between the flexible circuit board and silicon-based OLED

Inventive Principle:
Principle #35Parameter changes

2Strength

If reinforcement plates are added to the flexible circuit board to enhance structural integrity, then the structural strength is improved, but the device complexity increases

Engineering Contradiction:
Improvestructural integrityVSAvoidcircuit board structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The flexible circuit board is segmented into multiple functional layers including the flexible base plate, first wiring layer, and first reinforcement plate. This segmentation allows each layer to perform its specific function while contributing to overall structural integrity, balancing strength enhancement with manageable complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite material structures by combining the flexible base plate with the rigid first reinforcement plate. This composite design provides both flexibility and structural strength, improving structural integrity while maintaining the necessary flexibility for VR/AR device integration

Inventive Principle:
Principle #40Composite materials

3Reliability

If the convex portions and concave portions are made with optimal arc lengths for uniform particle dispersion, then the conductive particle uniformity is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveconductive particle uniformityVSAvoidarc length precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention specifies optimal arc length parameters for convex portions and corresponding concave portion dimensions that balance particle dispersion uniformity with manufacturing feasibility. These optimized parameters achieve reliable conductive particle distribution while maintaining reasonable manufacturing precision requirements for mass production

Inventive Principle:
Principle #35Parameter changes

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

Improves the reliability and stability of electrical connections by uniformly dispersing conductive particles and enhancing structural integrity, thereby ensuring consistent performance and durability of the display assembly.

Implementation Method 1

at least one part of the second pad is electrically connected to the first pad through a conductive adhesive, and the conductive adhesive includes conductive particles

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP4036981B1Display module and display apparatus
Publication Date: 2026.01.28 BOE TECHNOLOGY GROUP CO LTD
  • EP4036981B1 patent drawingFigure 1~2
  • EP4036981B1 patent drawingFigure 3~5
  • EP4036981B1 patent drawingFigure 6~8

AI summary

A display assembly and a display device are disclosed. The display assembly includes: a display panel including: a substrate, a driving circuit, and a first pad; a flexible circuit board, including: a flexible base plate, a first wiring layer and a first reinforcement plate, wherein the first wiring layer is on the flexible base plate and includes a main routing portion and a second pad, and the first reinforcement plate is on a side of the first wiring layer distal to the flexible base plate; an orthogonal projection of the main routing portion on the flexible base plate is within an orthogonal projection of the first reinforcement plate on the flexible base plate; the second pad is connected to the main routing portion, at least a part of the second pad is electrically connected to the first pad through a conductive adhesive, and the conductive adhesive includes conductive particles; in a first direction, the first reinforcement plate is outside the display panel, has a first edge proximal to the display panel; the first edge includes: convex portions and concave portions alternately arranged in a second direction to form a wave shape.