Flexible Display Substrate with Reduced Dielectric Constant

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Solution Overview

Problem

Flexible display devices face issues with electrical characteristics deterioration and afterimages due to electron charging and interfacial polarization on flexible substrates, affecting display quality and reliability.

Innovation Solution

A display device design incorporating substrates with reduced dielectric constants and inorganic layers to mitigate electron charging and interfacial polarization, featuring substrates with porosity ranging from 10% to 40% and dielectric constants of about 2 to 3, and inorganic layers with dielectric constants of 3.5 or less, made from materials like silica-based materials and polymers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a flexible substrate with conventional dielectric constant is used, then the substrate provides good mechanical flexibility and structural integrity, but electron charging and interfacial polarization occur causing electrical characteristic deterioration and afterimages

Engineering Contradiction:

Improveelectrical characteristic stabilityVSAvoidelectron charging and interfacial polarization

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by reducing the dielectric constant of the flexible substrate from conventional values (typically 3-4 for polyimide) to a lower range of 2-3. This parameter modification prevents electron charging and interfacial polarization at the interface between the substrate and inorganic layers, thereby eliminating afterimages and stabilizing electrical characteristics of thin-film transistors while maintaining mechanical flexibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by combining the flexible substrate with specific inorganic layers (such as buffer layers and barrier layers made from materials like silicon nitride, silicon oxide, or silicon oxynitride). This composite structure creates an interface that is resistant to electron charging and interfacial polarization, solving the reliability issue while preserving the flexible form factor

Inventive Principle:

Principle #40Composite materials

2Reliability

If substrates with reduced dielectric constant are used, then electron charging and interfacial polarization are suppressed improving display quality, but manufacturing precision and material selection become more critical

Engineering Contradiction:

Improvedisplay qualityVSAvoidsubstrate dielectric constant control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies a precise dielectric constant range of 2-3 for the flexible substrate, which is a narrowed parameter window compared to conventional substrates. This requires controlled manufacturing processes to achieve and maintain the target dielectric constant, increasing manufacturing precision requirements while ensuring optimal performance for preventing electron charging and interfacial polarization

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

The solution effectively maintains stable electrical characteristics of thin-film transistors and reduces afterimages, enhancing display quality and reliability by suppressing electron charging and interfacial polarization.

Implementation Method 1

electrical characteristics of thin-film transistors may deteriorate or vary due to electron charging and interfacial polarization in a flexible substrate

Methodology Applied

Scientific EffectElectron charging: Electrostatic Induction

Implementation Method 2

electrical characteristics of thin-film transistors may deteriorate or vary due to electron charging and interfacial polarization in a flexible substrate

Methodology Applied

Scientific EffectInterfacial polarization: Polarisation

Implementation Method 3

The second substrate is in contact with the at least one inorganic layer and has a dielectric constant less than a dielectric constant of the at least one inorganic layer

Methodology Applied

Scientific EffectDielectric constant: Dielectric Permittivity

Data Source

PatentUS20220293886A1Display device

Publication Date: 2022.09.15 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes: a first substrate; a second substrate disposed on the first substrate and including a plurality of voids; at least one inorganic layer disposed on the second substrate; at least one transistor disposed on the at least one inorganic layer; and a light-emitter disposed on the at least one transistor. The second substrate is in contact with the at least one inorganic layer and has a dielectric constant less than a dielectric constant of the at least one inorganic layer.