Resin Layer Configuration for Flexible Display Bending Stress

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Solution Overview

Problem

Existing display devices face damage to wiring layers when bent due to uneven resin layers causing local stress, which can lead to wiring damage during the bending process.

Innovation Solution

A method involving the formation of a first resin layer along the boundary of the area to be bent and subsequent injection of a second resin layer to create a flat, even neutral surface within the wiring layer, preventing damage during bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a resin layer is formed on the area to be bent to position the neutral surface near the wiring layer, then bending stress on the wiring layer is reduced, but if the resin layer is uneven, local stress is applied to the wiring layer causing damage

Engineering Contradiction:

Improvebending stress resistanceVSAvoidresin layer uniformity

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The resin layer is divided into two separate layers: a first resin layer formed on the area to be bent, and a second resin layer injected into the area surrounded by the first resin layer. This segmentation allows each layer to perform its specific function independently, with the first layer providing structural support and the second layer ensuring uniformity and stress distribution.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first resin layer acts as an intermediary structure that confines and guides the second resin layer during injection. This intermediary framework ensures that the second resin layer is uniformly distributed without creating local stress concentrations, thereby protecting the wiring layer from damage while maintaining bending stress resistance.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Area of stationary object

If the area to be bent is made narrow to hide FPC and IC, then the apparent frame area is reduced and display visibility is improved, but the wiring layer becomes more susceptible to bending damage

Engineering Contradiction:

Improveapparent frame areaVSAvoidwiring layer integrity

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The solution moves from a single-layer resin approach to a two-dimensional layered resin structure. The first resin layer forms a boundary framework while the second resin layer fills the interior space, creating a three-dimensional protective structure that maintains wiring integrity even in narrow bent areas.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The dual resin layer structure creates a composite protective system where the first resin layer provides structural confinement and the second resin layer provides uniform stress distribution. This composite approach enhances wiring layer reliability in the bent area without increasing the apparent frame area.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10573849B2Method for manufacturing display device

Publication Date: 2020.02.25 MAGNOLIA WHITE CORP

AI summary

A flexible substrate including a display area and a area to be bent, the area to be bent being provided with a wiring layer and not overlapping the display area. A first resin layer that extends along a boundary of the area to be bent and continuously surrounds the area to be bent is formed. Subsequently, a second resin layer is injected into an area surrounded by the first resin layer.