Flexible Flat Panel Displays

Flexible Flat Panel Displays
Contents
Series Editor’s Foreword
List of Contributors
1 Introduction
1.1 Toward Flexible Mobile Devices
1.2 Flexible Display Layers
1.3 Other Flexible Displays and Manufacturing
2 Engineered Films for Display Technology
2.1 Introduction
2.2 Factors Influencing Film Choice
2.2.1 Application Area
2.2.2 Physical Form/Manufacturing Process
2.2.3 Film Property Set
2.2.3.1 Polymer Type
2.2.3.2 Optical Clarity
2.2.3.3 Birefringence
2.2.3.4 The Effect of Thermal Stress on Dimensional Reproducibility
2.2.3.5 Low-bloom Films
2.2.3.6 Solvent and Moisture Resistance
2.2.3.7 The Effect of Mechanical Stress on Dimensional Reproducibility
2.2.3.8 Surface Quality
2.3 Summary of Key Properties of Base Substrates
2.4 Planarizing Coatings
2.5 Examples of Film in Use
2.6 Concluding Remarks
Acknowledgments
3 Liquid Crystal Optical Coatings for Flexible Displays
3.1 Introduction
3.2 LCN Technology
3.3 Thin-film Polarizers
3.3.1 Smectic Polarizers
3.3.2 Cholesteric Polarizers
3.4 Thin-film Retarders
3.4.1 Reactive Mesogen Retarders
3.4.2 Chromonic Liquid Crystal-based Retarders
3.4.3 Liquid Crystal Alignment and Patterned Retarders
3.5 Color Filters
3.6 Conclusion
4 Large Area Flexible Organic Field-effect Transistor Fabrication
4.1 Introduction
4.2 Substrates
4.3 Photolithography
4.4 Printing for Roll-to-roll Fabrication
4.4.1 Inkjet Printing
4.4.2 Gravure and Flexographic Printing
4.4.3 Screen Printing
4.4.4 Aerosol Jet Printing
4.4.5 Contact Printing
4.4.6 Meniscus Dragging
4.5 Conclusions
5 Metallic Nanowires, Promising Building Nanoblocks for Flexible Transparent Electrodes
5.1 Introduction
5.2 TEs Based on Metallic Nanowires
5.2.1 Metallic Nanowires, New Building Nanoblocks
5.2.2 Random Network Fabrication
5.2.3 Optical Characterization
5.2.4 Electrical Characterization
5.2.5 Mechanical Aspect
5.3 Application to Flexible Displays
5.3.1 Touch Screens
5.3.2 Light-emitting Diodes Displays
5.3.3 Electrochromic Flexible Displays
5.3.4 Other Displays
5.4 Conclusions
6 Optically Clear Adhesives for Display Assembly
6.1 Introduction
6.2 OCA Definition and General Performance Specifications
6.3 Application Examples and Challenges
6.3.1 Outgassing Tolerant Adhesives
6.3.2 Anti-whitening Adhesives
6.3.3 Non-corrosive OCAs
6.3.4 Compliant OCAs for High Ink-step Coverage and Mura-free Assembly of LCD Panels
6.3.5 Reworkable OCAs
6.3.6 Barrier Adhesives
6.4 Summary and Remaining Challenges
7 Self-healing Polymer Substrates
7.1 Introduction
7.2 General Classes of Self-healing Polymers
7.2.1 Types of Dynamic Bonds in Self-healing Polymers
7.2.2 Supramolecularly Crosslinked Self-healing Polymers
7.2.2.1 Hydrogen Bonding
7.2.2.2 π–π Stacking
7.2.2.3 Ionic Interactions
7.2.3 Dynamic-covalently Crosslinked Self-healing Polymers
7.2.3.1 Cycloaddition Reactions
7.2.3.2 Disulfides-based Reversible Reactions
7.2.3.3 Acylhydrazones
7.2.3.4 Boronate Esters
7.3 Special Considerations for Flexible Self-healing Polymers
7.4 Incorporation of Electrically Conductive Components
7.4.1 Metallic Conductors
7.4.2 Conductive Polymers
7.4.3 Carbon Materials
7.4.4 Polymerized Ionic Liquids
7.5 Additional Possibilities Enabled by Three-dimensional Printing
7.6 Concluding Remarks
8 Flexible Glass Substrates
8.1 Introduction
8.2 Display Glass Properties
8.2.1 Overview of Display Glass Types
8.2.2 Glass Properties
8.2.2.1 Optical Properties
8.2.2.2 Chemical Properties
8.2.2.3 Thermal Properties
8.2.2.4 Surface Properties
8.2.2.5 Permeability
8.3 Manufacturing of Thin “Flexible’’ Glass
8.3.1 Float and Downdraw Technology for Special Glass
8.3.2 Limits
8.3.2.1 Thickness Limits for Production
8.3.2.2 Surface Quality Limits for Production
8.4 Mechanical Properties
8.4.1 Thin Glass and Glass/Plastic Substrates
8.4.2 Mechanical Test Methods for Flexible Glasses
8.5 Improvement in Mechanical Properties of Glass
8.5.1 Reinforcement of Glass Substrates
8.5.1.1 Principal Methods of Reinforcement
8.5.1.2 Materials for Reinforcement Coatings
8.6 Processing of Flexible Glass
8.6.1 Cleaning
8.6.2 Separation
8.7 Current Thin Glass Substrate Applications and Trends
8.7.1 Displays
8.7.2 Touch Panels
8.7.3 Sensors
8.7.4 Wafer-level Chip Size Packaging
9 Toward a Foldable Organic Light-emitting Diode Display
9.1 Panel Stack-up Comparison: Glass-based and Plastic-based Organic Light-emitting Diode
9.1.1 Technology for Improving Contrast Ratio of OLED Display
9.2 CF–OLED for Achieving Foldable OLED Display
9.2.1 Mechanism of the AR coating in CF–OLED
9.2.2 Optical Performance of CF–OLED
9.3 Mechanical Performance of CF–OLED
9.3.1 Bi-directional Folding Performance and Minimum Folding Radius of SPS CF–OLED
9.4 Touch Panel Technology of CF–OLED
9.5 Foldable Application
9.5.1 Foldable Technology Summary
9.5.1.1 Polymer Substrates and Related Debonding Technology
9.5.1.2 Alternative TFT Types to LTPS
9.5.1.3 Encapsulation Systems to Protect Devices against Moisture
9.5.2 Novel and Next-generation Display Technologies
10 Flexible Reflective Display Based on Cholesteric Liquid Crystals
10.1 Introduction to Cholesteric Liquid Crystal
10.2 Reflection of CLC
10.3 Bistable CLC Reflective Display
10.4 Color Design of Reflective Bistable CLC Display
10.4.1 Mono-color Display
10.4.2 Full-color Display
10.5 Transitions between Cholesteric States
10.5.1 Transition from Planar State to Focal Conic State
10.5.2 Transition from Focal Conic State to Homeotropic State
10.5.3 Transition from Homotropic State to Focal Conic State
10.5.4 Transition from Homeotropic State to Transient Planar State
10.5.5 Transition from Transient Planar State to Planar State
10.6 Driving Schemes
10.6.1 Response to Voltage Pulse
10.6.2 Conventional Driving Scheme
10.6.3 Dynamic Driving Scheme
10.6.4 Thermal Driving Scheme
10.6.5 Flow Driving Scheme
10.7 Flexible Bistable CLC Reflective Display
10.8 Bistable Encapsulated CLC Reflective Display
10.9 Production of Flexible CLC Reflective Displays
10.9.1 Color e-Book with Single-layered Structure
10.9.2 Roll-to Roll E-paper and Applications
10.10 Conclusion
11 Electronic Paper
11.1 Introduction
11.2 Electrophoretic Display
11.2.1 Development History and Working Principle
11.2.2 Materials
11.2.2.1 Colored Particles/Pigments
11.2.2.2 Capsule Shell Materials
11.2.2.3 Suspending Medium (Mobile Phase)
11.2.2.4 Charge Control Agents
11.2.2.5 Stabilizers
11.2.3 Device Fabrication
11.2.4 Flexible EPD
11.3 Electrowetting Displays
11.3.1 Development History and Working Principle
11.3.2 Materials
11.3.2.1 Absorbing (Dyed) Hydrophobic Liquid
11.3.3 Device Fabrication
11.3.4 Flexible EWD
11.4 Other E-paper Display Technologies and Feasibility of Flexibility
11.4.1 PCD
11.4.2 LPD
11.5 Cholesteric (Chiral Nematic) LCDs
11.6 Electrochromic Displays
11.7 MEMS Displays
12 Encapsulation of Flexible Displays: Background, Status, and Perspective
12.1 Introduction
12.2 Background
12.3 Multilayer TFE Technology
12.3.1 Multilayer Approach
12.3.2 Inorganic Layer Deposition Techniques
12.3.3 Organic Layer Deposition Techniques
12.4 Current Technology Implementation
12.5 Future Developments
12.6 Conclusions
Acknowledgments
13 Flexible Battery Fundamentals
13.1 Introduction
13.2 Structural and Materials Aspects
13.2.1 Shape
13.2.2 One-dimensional Batteries
13.2.3 Two-dimensional Planar Batteries
13.2.4 Solid versus Liquid Electrolyte
13.2.5 Carbon Additives
13.3 Examples of Flexible Batteries
13.4 Future Perspectives
14 Flexible and Large-area X-ray Detectors
14.1 Introduction
14.2 Direct and Indirect Detectors
14.3 Thin-film Photodiode Sensors for Indirect-conversion Detectors
14.3.1 Performance Parameters
14.3.2 Photodiode Materials on Plastic Substrates
14.3.2.1 Amorphous Silicon
14.3.2.2 Organic Semiconductor Materials
14.4 TFT Array
14.4.1 Pixel Architecture and Transistor Requirements
14.4.2 Flexible Transistor Arrays
14.5 Medical-grade Detector
14.6 Summary and Outlook
15 Interacting with Flexible Displays
15.1 Introduction
15.2 Touch Technologies in Non-Flexible Displays
15.2.1 Resistive Touch Sensors
15.2.2 4-Wire Resistive
15.2.3 5-Wire Resistive
15.2.4 Capacitive Sensing
15.2.5 Surface Capacitive
15.2.6 Projected Capacitive
15.2.7 Infrared Sensing
15.2.8 Surface Acoustic Wave
15.2.9 Bending Wave Technologies
15.3 Touch Technologies in Flexible Displays
15.4 Summary
16 Mechanical Durability of Inorganic Films on Flexible Substrates
16.1 Introduction
16.2 Flexible Display Materials
16.2.1 Property Contrast between Coating and Substrate Materials
16.2.2 Determination of Mechanical Properties of Inorganic Coatings
16.3 Stress and Strain Analyses
16.3.1 Intrinsic, Thermal, and Hygroscopic Stresses and Strains
16.3.2 Strain Analysis of Multilayer Films under Bending
16.3.3 Critical Radius of Curvature
16.4 Failure Mechanics of Brittle Films
16.4.1 Damage Phenomenology under Tensile and Compressive Loading
16.4.2 Experimental Methods
16.4.3 Fracture Mechanics Analysis
16.4.4 Role of Internal Stresses
16.4.5 Influence of Film Thickness on Critical Strain
16.5 Durability Influences
16.5.1 Influence of Temperature
16.5.2 Fatigue
16.5.3 Corrosion
16.6 Toward Robust Layers
16.7 Final Remarks
Acknowledgments
Nomenclature
17 Roll-to-roll Production Challenges for Large-area Printed Electronics
17.1 Introduction
17.2 Infrastructure
17.3 Equipment
17.4 Materials
17.5 Processing
17.6 Summary
18 Direct Ink Writing of Touch Sensors and Displays: Current Developments and Future Perspectives
18.1 Introduction
18.2 DIW and Ink Development
18.3 Applications of DIW for Displays and Touch Sensors
18.4 Future Challenges and Opportunities
19 Flexible Displays for Medical Applications
19.1 Introduction
19.1.1 Flexible Displays in Medicine
19.1.2 A Brief Historical Perspective
19.1.3 Application of Flexible Displays for Biochemical Analysis
19.1.4 OLEDs and Organic Photodiodes as Optical Excitation Sources and Detectors
19.1.5 Device Integration
19.1.6 Fluorescence, Photoluminescence Intensity, and Decay-time Sensing
19.2 Flexible OLEDs for Oxygen Sensors
19.3 Glucose Sensing Using Flexible Display Technology
19.4 POC Disease Diagnosis and Pathogen Detection Using Flexible Display Optoelectronics
19.5 Flexible Display Technology for Multi-analyte Sensor Array Platforms
19.5.1 Integrated LOC and Flexible Display Devices
19.5.2 Multiplexed Sensor Platforms
19.6 Medical Diagnostic Displays
19.7 Wearable Health Monitoring Devices Based on Flexible Displays
19.7.1 Monitoring Vital Signs Using Flexible Display Technology
19.7.2 Flexible Display Technology for Phototherapy
19.7.3 Smart Clothing Using Flexible Display Technology
19.8 Competing Technologies, Challenges, and Future Trends
19.9 Conclusion
Acknowledgment
Conflicts of Interest
Index
EULA