Flexible Substrate with Concave Relief Pattern for Curling Control

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Solution Overview

Problem

Current flexible display devices face issues with unwanted curling when peeling off the flexible substrate from a carrier substrate due to film stress, leading to potential damage and defective products.

Innovation Solution

A flexible base substrate with a first flexible film layer featuring a plurality of concave parts on its lower surface, which reduces tensile stress through alternating film thicknesses and protrusions, preventing curling and ensuring controlled bending direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flexible substrate is covered with an inorganic film layer, then the display device structure is complete and functional, but film stress causes unwanted curl when the flexible substrate is peeled off from the carrier substrate

Engineering Contradiction:

Improvedisplay device functionalityVSAvoidsubstrate curling

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

The patent introduces a release pattern structure that segments the interface between the flexible substrate and carrier substrate. This patterned release layer creates discrete separation points, allowing controlled peeling while managing film stress distribution across the substrate surface.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The release pattern structure provides localized stress relief at specific regions where peeling occurs. By concentrating release functionality at particular locations rather than uniformly across the entire substrate, the patent enables controlled separation while maintaining structural integrity in other areas.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If the flexible substrate is peeled off from the rigid carrier substrate, then the display device can be transferred to the final substrate, but the film stress causes unwanted curl that may damage the display device

Engineering Contradiction:

Improvesubstrate transfer processVSAvoidfilm stress-induced curling

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The release pattern structure is prepared in advance on the carrier substrate before the flexible substrate is fully formed. This preliminary preparation of the release interface enables controlled peeling later in the process, preventing stress-induced curling during the transfer operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The release pattern structure acts as an intermediary layer between the flexible substrate and carrier substrate. This intermediate structure facilitates controlled separation by providing a designated interface that manages the peeling process, reducing harmful stress effects on the display device.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10978500B2Flexible base substrate and fabrication method thereof

Publication Date: 2021.04.13 BOE TECHNOLOGY GROUP CO LTD

AI summary

Embodiments of the present invention provide a flexible base substrate and a fabrication method thereof. The flexible base substrate comprises: a first flexible film layer, having an upper surface and a lower surface opposite to each other, wherein a plurality of concave parts are arranged on the lower surface of the first flexible film layer.