Flexible Display Protection Layers Offset Thermal Stress

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Solution Overview

Problem

Conventional manufacturing methods for flexible display apparatuses often result in cracks in the insulation layers due to heat and pressure during the manufacturing process, which can damage the display elements and thin films.

Innovation Solution

A manufacturing method involving a sacrificial layer, a flexible substrate, and protection layers with opposite thermal expansion coefficients or stresses is used, where a sacrificial layer is formed on a carrier, a flexible substrate is built on this layer, and protection layers are applied to absorb and offset thermal stresses, preventing cracks during separation from the carrier using a laser beam.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If heat and pressure are applied during the manufacturing process to form thin films and display elements, then the display elements and thin films can be formed on the flexible substrate, but cracks occur in the insulation layers

Engineering Contradiction:

Improveformation of display elements and thin filmsVSAvoidintegrity of insulation layers

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

A protection layer is formed on the flexible substrate before forming the display elements and thin films. This protection layer is prepared in advance to prevent cracks in the insulation layers during subsequent heat and pressure application, allowing the manufacturing process to proceed without damaging the insulation layers.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protection layer acts as an intermediary between the heat/pressure source and the insulation layers. It absorbs and distributes the thermal stress and mechanical pressure, preventing direct transmission of harmful forces to the insulation layers while still allowing the display elements and thin films to be formed.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the flexible substrate is separated from the carrier by removing the sacrificial layer, then the flexible substrate can be released, but thermal expansion stress may cause cracks in the insulation layers

Engineering Contradiction:

Improveseparation of flexible substrate from carrierVSAvoidintegrity of insulation layers

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The protection layer is formed in advance on the flexible substrate before the substrate is separated from the carrier. This pre-formed protection layer is designed to withstand the thermal expansion stress that occurs during separation, preventing cracks in the insulation layers while allowing easy release of the flexible substrate.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The protection layer is designed with specific material properties (thermal expansion coefficient, mechanical strength) that allow it to accommodate thermal expansion stress during the separation process. By changing the parameters of the protection layer material, the system can withstand the stress without causing cracks in the insulation layers.

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

This method effectively prevents cracks in the insulation layers and encapsulation layers, ensuring the integrity and durability of the flexible display apparatus by managing thermal expansion and stress, thereby protecting the organic light-emitting devices and thin films from damage.

Implementation Method 1

separating the flexible substrate from the carrier may include separating the carrier and the flexible substrate from each other by irradiating a laser beam on an opposite side of the carrier to a side of the carrier on which the sacrificial layer is formed, and removing at least a portion of the sacrificial layer

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

forming, on the first protection layer, a second protection layer, which has an opposite sign of a thermal expansion coefficient to the first protection layer

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS9911918B2Method of manufacturing flexible display apparatus

Publication Date: 2018.03.06 SAMSUNG DISPLAY CO LTD

AI summary

A manufacturing method of a flexible display apparatus includes forming a sacrificial layer on a carrier, forming a flexible substrate on the sacrificial layer, forming a display element on the flexible substrate, forming a first protection layer on the display element, forming, on the first protection layer, a second protection layer, which has an opposite sign of a thermal expansion coefficient to the first protection layer, separating the flexible substrate from the carrier by removing at least a portion of the sacrificial layer, and separating the first protection layer from the first protection layer.