Flexible Display Fabrication Using Patterned Release Layer

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Solution Overview

Problem

The existing methods for fabricating flexible displays, which involve using a glass carrier and a release layer, require high-energy processes like laser scanning to separate the flexible substrate, increasing manufacturing costs and damaging device characteristics.

Innovation Solution

A method where a patterned release layer with a higher adhesive force to the flexible substrate than to the carrier substrate is used, allowing for simultaneous cutting and separation without high-energy processes, reducing costs and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a laser process is used to separate the flexible substrate from the glass carrier, then the release layer can be effectively separated, but the manufacturing cost increases and the transistors in the display are damaged causing deteriorated device characteristics

Engineering Contradiction:

Improvedevice characteristicsVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the adhesive force parameter of the release layer by selecting specific materials (amorphous silicon with controlled thickness of 10-1000 nm) to achieve differential adhesion. The release layer has stronger adhesion to the flexible substrate than to the glass carrier, enabling mechanical separation without laser processes, thus resolving the contradiction between manufacturing cost and device reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the laser-based thermal/mechanical separation system with a mechanically-driven separation system based on differential adhesion forces. By designing the release layer with appropriate adhesive properties, the separation process becomes a simple mechanical peeling action that avoids the harmful laser process, thereby reducing manufacturing cost while preserving device characteristics

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of manufacture

If a laser process is used to separate the flexible substrate, then the release layer can be separated, but the device characteristics of the display deteriorate due to damage

Engineering Contradiction:

Improverelease processVSAvoiddevice characteristics

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent converts the potential harm of strong adhesion (which could make separation difficult) into a benefit by designing the release layer to have selectively strong adhesion to the flexible substrate. This differential adhesion design allows the release layer to remain firmly attached to the flexible substrate during fabrication while enabling easy separation from the glass carrier through mechanical means alone, avoiding laser damage to devices

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If the adhesive force between the release layer and flexible substrate is stronger than between the release layer and carrier substrate, then the patterned release layer can be easily released from the carrier substrate, but the release layer must be precisely patterned

Engineering Contradiction:

Improverelease processVSAvoidpatterned release layer

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by creating a patterned release layer with specific geometric shapes (such as pixel patterns matching the display structure) rather than using a continuous release layer. This segmentation allows the release layer to be selectively removed from the carrier substrate while maintaining strong adhesion to the flexible substrate in the required areas, enabling easy separation without requiring extremely high manufacturing precision for the pattern itself

Inventive Principle:

Principle #1Segmentation

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

This approach reduces manufacturing costs and preserves device characteristics by avoiding high-energy processes, enabling a flexible display with improved performance and longevity.

Implementation Method 1

an adhesive force between the patterned release layer and the flexible substrate is larger than an adhesive force between the patterned release layer and the carrier substrate

Methodology Applied

Scientific EffectAdhesive force: Adhesive

Data Source

PatentUS8940208B2Fabricating method of flexible display and flexible display

Publication Date: 2015.01.27 AU OPTRONICS CORP

AI summary

A fabricating method of a flexible display is provided. A release layer is formed on a carrier substrate. The release layer is patterned to form a patterned release layer. A flexible substrate is formed on the patterned release layer, wherein the flexible substrate covers the patterned release layer and a portion of the flexible substrate contacts the carrier substrate. An adhesive force between the patterned release layer and the flexible substrate is larger than an adhesive force between the patterned release layer and the carrier substrate. A device layer is formed on the flexible substrate. A display layer is formed on the device layer. The flexible substrate and patterned release layer are cut simultaneously. The patterned release layer being cut is separated from the carrier substrate, wherein the flexible substrate, the device layer and the display layer which have been cut are sequentially disposed on the separated patterned release layer.