Flexible OLED Substrate with Polysilicon Protrusions for Rift Prevention

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Solution Overview

Problem

Existing organic light emitting diode (OLED) displays with flexible substrates face challenges in maintaining structural integrity and preventing rifts when repeatedly bent, affecting the quality and reliability of the display.

Innovation Solution

A flexible substrate is manufactured with a polysilicon layer having irregularly or regularly arranged protrusions, and a second flexible layer is formed on top, using a method that includes crystallization by excimer laser annealing or sequential lateral solidification, with a barrier layer to enhance moisture prevention and surface roughness, ensuring the substrate's durability and performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If a flexible substrate is used in OLED displays, then thickness and weight are reduced, but structural integrity and resistance to rifts during repeated bending deteriorate

Engineering Contradiction:
Improveweight of displayVSAvoidstructural integrity during bending
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent employs a composite flexible substrate structure consisting of multiple layers including a base flexible layer, a polysilicon layer with protrusions, and a second flexible layer. This multi-layer composite construction enhances structural integrity and resistance to rifts during repeated bending while maintaining the overall flexibility and reduced weight of the display device.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If a polysilicon layer with protrusions is formed, then surface roughness and moisture prevention are enhanced, but manufacturing complexity increases

Engineering Contradiction:
Improvemoisture preventionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The protrusions are formed on the polysilicon layer during the crystallization process itself, rather than requiring a separate post-processing step. The excimer laser annealing or sequential lateral solidification method inherently creates the protrusion structure as the amorphous silicon crystallizes, thereby preventing moisture penetration while avoiding additional manufacturing complexity.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If excimer laser annealing or sequential lateral solidification is used for crystallization, then protrusions are formed to prevent rifts, but manufacturing time and energy consumption increase

Engineering Contradiction:
Improverift prevention during bendingVSAvoidcrystallization processing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent utilizes phase transition of silicon from amorphous to crystalline state through excimer laser annealing or sequential lateral solidification. This phase transition process inherently forms protrusions on the polysilicon layer surface that prevent rift formation during bending. The method achieves both rift prevention and protrusion formation in a single crystallization step, optimizing manufacturing efficiency.

Inventive Principle:
Principle #36Phase transitions

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

The solution provides a high-quality OLED display that maintains structural integrity and prevents rifts even with repeated bending, ensuring a reliable and high-performance flexible OLED display.

Implementation Method 1

The crystallization may be performed by an excimer laser annealing method

Methodology Applied
Scientific EffectLaser annealing: Annealing

Implementation Method 2

The crystallization may be performed by an excimer laser annealing method

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 3

The crystallization may be performed by the sequential lateral solidification method

Methodology Applied
Scientific EffectSolidification: Freezing

Implementation Method 4

an organic light emitting diode emitting light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2790237B1Organic light emitting diode display with flexible substrate and method of manufacturing the same
Publication Date: 2017.11.29 SAMSUNG DISPLAY CO LTD
  • EP2790237B1 patent drawingFigure 1
  • EP2790237B1 patent drawingFigure 2
  • EP2790237B1 patent drawingFigure 3

AI summary

A flexible substrate (100), a method of manufacturing the same, and an organic light emitting diode display, the flexible substrate (100) including a first flexible layer (10); a polysilicon layer (20) on the first flexible layer, the polysilicon layer (20) having a plurality of protrusions (7) on a surface thereof; and a second flexible layer (30) on the polysilicon layer.