Darran R. Cairns, PhD, is a member of the Faculty in the School of Science & Engineering at University of Missouri - Kansas City, USA. His research interests include solution-based processing of composite materials including sol-gel materials, nano-composite materials, and liquid crystalline materials and composites.

Dirk J. Broer, is a Polymer Chemist specialized in polymer structuring and self-organizing polymer networks. This entails the development of polymers with new functionalities and integrating them into devices to meet industrial and societal challenges in the fields of sustainable energy, water-management, healthcare and personal comfort.

Gregory P. Crawford, PhD, is President of Miami University, USA, and Professor of Physics. His research interests include liquid crystal and polymer materials for display and biotechnology applications. He is the editor of the first edition of Flexible Flat Panel Displays (2005).

Series Editor's Foreword xv List of Contributors xvii 1 Introduction 1Darran R. Cairns, Gregory P. Crawford, and Dirk J. Broer 1.1 Toward Flexible Mobile Devices 1 1.2 Flexible Display Layers 2 1.3 Other Flexible Displays and Manufacturing 2 2 Engineered Films for Display Technology 5W.A. MacDonald 2.1 Introduction 5 2.2 Factors Influencing Film Choice 5 2.2.1 Application Area 5 2.2.2 Physical Form/Manufacturing Process 6 2.2.3 Film Property Set 7 2.2.3.1 Polymer Type 7 2.2.3.2 Optical Clarity 9 2.2.3.3 Birefringence 10 2.2.3.4 The Effect of Thermal Stress on Dimensional Reproducibility 10 2.2.3.5 Low-bloom Films 11 2.2.3.6 Solvent and Moisture Resistance 12 2.2.3.7 The Effect of Mechanical Stress on Dimensional Reproducibility 16 2.2.3.8 Surface Quality 18 2.3 Summary of Key Properties of Base Substrates 19 2.4 Planarizing Coatings 21 2.5 Examples of Film in Use 23 2.6 Concluding Remarks 24 Acknowledgments 25 3 Liquid Crystal Optical Coatings for Flexible Displays 27Owain Parri, Johan Lub, and Dirk J. Broer 3.1 Introduction 27 3.2 LCN Technology 27 3.3 Thin-film Polarizers 29 3.3.1 Smectic Polarizers 29 3.3.2 Cholesteric Polarizers 32 3.4 Thin-film Retarders 34 3.4.1 Reactive Mesogen Retarders 35 3.4.2 Chromonic Liquid Crystal-based Retarders 37 3.4.3 Liquid Crystal Alignment and Patterned Retarders 37 3.5 Color Filters 41 3.6 Conclusion 43 4 Large Area Flexible Organic Field-effect Transistor Fabrication 47Zachary A. Lamport, Marco Roberto Cavallari, and Ioannis Kymissis 4.1 Introduction 47 4.2 Substrates 48 4.3 Photolithography 49 4.4 Printing for Roll-to-roll Fabrication 52 4.4.1 Inkjet Printing 52 4.4.2 Gravure and Flexographic Printing 55 4.4.3 Screen Printing 56 4.4.4 Aerosol Jet Printing 56 4.4.5 Contact Printing 58 4.4.6 Meniscus Dragging 60 4.5 Conclusions 62 5 Metallic Nanowires, Promising Building Nanoblocks for Flexible Transparent Electrodes 67Jean-Pierre Simonato 5.1 Introduction 67 5.2 TEs Based on Metallic Nanowires 68 5.2.1 Metallic Nanowires, New Building Nanoblocks 68 5.2.2 Random Network Fabrication 69 5.2.3 Optical Characterization 70 5.2.4 Electrical Characterization 71 5.2.5 Mechanical Aspect 73 5.3 Application to Flexible Displays 73 5.3.1 Touch Screens 73 5.3.2 Light-emitting Diodes Displays 74 5.3.3 Electrochromic Flexible Displays 76 5.3.4 Other Displays 77 5.4 Conclusions 78 6 Optically Clear Adhesives for Display Assembly 85Albert I. Everaerts 6.1 Introduction 85 6.2 OCA Definition and General Performance Specifications 86 6.3 Application Examples and Challenges 89 6.3.1 Outgassing Tolerant Adhesives 90 6.3.2 Anti-whitening Adhesives 91 6.3.3 Non-corrosive OCAs 92 6.3.4 Compliant OCAs for High Ink-step Coverage and Mura-free Assembly of LCD Panels 94 6.3.5 Reworkable OCAs 102 6.3.6 Barrier Adhesives 103 6.4 Summary and Remaining Challenges 104 7 Self-healing Polymer Substrates 107Progyateg Chakma, Zachary A. Digby, and Dominik Konkolewicz 7.1 Introduction 107 7.2 General Classes of Self-healing Polymers 108 7.2.1 Types of Dynamic Bonds in Self-healing Polymers 109 7.2.2 Supramolecularly Crosslinked Self-healing Polymers 109 7.2.2.1 Hydrogen Bonding 110 7.2.2.2 ¿-¿ Stacking 110 7.2.2.3 Ionic Interactions 111 7.2.3 Dynamic-covalently Crosslinked Self-healing Polymers 111 7.2.3.1 Cycloaddition Reactions 111 7.2.3.2 Disulfides-based Reversible Reactions 112 7.2.3.3 Acylhydrazones 113 7.2.3.4 Boronate Esters 113 7.3 Special Considerations for Flexible Self-healing Polymers 114 7.4 Incorporation of Electrically Conductive Components 115 7.4.1 Metallic Conductors 115 7.4.2 Conductive Polymers 116 7.4.3 Carbon Materials 118 7.4.4 Polymerized Ionic Liquids 119 7.5 Additional Possibilities Enabled by Three-dimensional Printing 119 7.6 Concluding Remarks 121 8 Flexible Glass Substrates 129Armin Plichta, Andreas Habeck, Silke Knoche, Anke Kruse, Andreas Weber, and Norbert Hildebrand 8.1 Introduction 129 8.2 Display Glass Properties 129 8.2.1 Overview of Display Glass Types 129 8.2.2 Glass Properties 130 8.2.2.1 Optical Properties 130 8.2.2.2 Chemical Properties 130 8.2.2.3 Thermal Properties 131 8.2.2.4 Surface Properties 132 8.2.2.5 Permeability 133 8.3 Manufacturing of Thin "Flexible'' Glass 134 8.3.1 Float and Downdraw Technology for Special Glass 134 8.3.2 Limits 135 8.3.2.1 Thickness Limits for Production 135 8.3.2.2 Surface Quality Limits for Production 136 8.4 Mechanical Properties 137 8.4.1 Thin Glass and Glass/Plastic Substrates 137 8.4.2 Mechanical Test Methods for Flexible Glasses 137 8.5 Improvement in Mechanical Properties of Glass 140 8.5.1 Reinforcement of Glass Substrates 140 8.5.1.1 Principal Methods of Reinforcement 141 8.5.1.2 Materials for Reinforcement Coatings 141 8.6 Processing of Flexible Glass 142 8.6.1 Cleaning 143 8.6.2 Separation 143 8.7 Current Thin Glass Substrate Applications and Trends 144 8.7.1 Displays 145 8.7.2 Touch Panels 145 8.7.3 Sensors 145 8.7.4 Wafer-level Chip Size Packaging 146 9 Toward a Foldable Organic Light-emitting Diode Display 149Meng-Ting Lee, Chi-Shun Chan, Yi-Hong Chen, Chun-Yu Lin, Annie Tzuyu Huang, Jonathan HT Tao, and Chih-Hung Wu 9.1 Panel Stack-up Comparison: Glass-based and Plastic-based Organic Light-emitting Diode 149 9.1.1 Technology for Improving Contrast Ratio of OLED Display 151 9.2 CF-OLED for Achieving Foldable OLED Display 153 9.2.1 Mechanism of the AR coating in CF-OLED 154 9.2.2 Optical Performance of CF-OLED 155 9.3 Mechanical Performance of CF-OLED 157 9.3.1 Bi-directional Folding Performance and Minimum Folding Radius of SPS Cf-oled 159 9.4 Touch Panel Technology of CF-OLED 160 9.5 Foldable Application 162 9.5.1 Foldable Technology Summary 162 9.5.1.1 Polymer Substrates and Related Debonding Technology 162 9.5.1.2 Alternative TFT Types to LTPS 162 9.5.1.3 Encapsulation Systems to Protect Devices against Moisture 163 9.5.2 Novel and Next-generation Display Technologies 163 10 Flexible Reflective Display Based on Cholesteric Liquid Crystals 167Deng-Ke Yang, J. W. Shiu, M. H. Yang, and Janglin Che 10.1 Introduction to Cholesteric Liquid Crystal 167 10.2 Reflection of CLC 169 10.3 Bistable CLC Reflective Display 171 10.4 Color Design of Reflective Bistable CLC Display 173 10.4.1 Mono-color Display 173 10.4.2 Full-color Display 173 10.5 Transitions between Cholesteric States 175 10.5.1 Transition from Planar State to Focal Conic State 175 10.5.2 Transition from Focal Conic State to Homeotropic State 177 10.5.3 Transition from Homotropic State to Focal Conic State 177 10.5.4 Transition from Homeotropic State to Transient Planar State 178 10.5.5 Transition from Transient Planar State to Planar State 179 10.6 Driving Schemes 181 10.6.1 Response to Voltage Pulse 181 10.6.2 Conventional Driving Scheme 183 10.6.3 Dynamic Driving Scheme 183 10.6.4 Thermal Driving Scheme 185 10.6.5 Flow Driving Scheme 186 10.7 Flexible Bistable CLC Reflective Display 187 10.8 Bistable Encapsulated CLC Reflective Display 188 10.9 Production of Flexible CLC Reflective Displays 189 10.9.1 Color e-Book with Single-layered Structure 191 10.9.2 Roll-to Roll E-paper and Applications 195 10.10 Conclusion 202 11 Electronic Paper 207Guofu Zhou, Alex Henzen, and Dong Yuan 11.1 Introduction 207 11.2 Electrophoretic Display 210 11.2.1 Development History and Working Principle 210 11.2.2 Materials 212 11.2.2.1 Colored Particles/Pigments 212 11.2.2.2 Capsule Shell Materials 213 11.2.2.3 Suspending Medium (Mobile Phase) 213 11.2.2.4 Charge Control Agents 213 11.2.2.5 Stabilizers 213 11.2.3 Device Fabrication 214 11.2.4 Flexible EPD 215 11.3 Electrowetting Displays 216 11.3.1 Development History and Working Principle 216 11.3.2 Materials 218 11.3.2.1 Absorbing (Dyed) Hydrophobic Liquid 218 11.3.3 Device Fabrication 220 11.3.4 Flexible EWD 221 11.4 Other E-paper Display Technologies and Feasibility of Flexibility 222 11.4.1 Pcd 222 11.4.2 Lpd 223 11.5 Cholesteric (Chiral Nematic) LCDs 224 11.6 Electrochromic Displays 224 11.7 MEMS Displays 226 12 Encapsulation of Flexible Displays: Background, Status, and Perspective 229Lorenza Moro and Robert Jan Visser 12.1 Introduction 229 12.2 Background 230 12.3 Multilayer TFE Technology 234 12.3.1 Multilayer Approach 234 12.3.2 Inorganic Layer Deposition Techniques 237 12.3.3 Organic Layer Deposition Techniques 238 12.4 Current Technology Implementation 242 12.5 Future Developments 246 12.6 Conclusions 249 Acknowledgments 250 13 Flexible Battery Fundamentals 255Nicholas Winch, Darran R. Cairns, and Konstantinos A. Sierros 13.1 Introduction 255 13.2 Structural and Materials Aspects 256 13.2.1 Shape 257 13.2.2 One-dimensional Batteries 257 13.2.3 Two-dimensional Planar Batteries 258 13.2.4 Solid versus Liquid Electrolyte 259 13.2.5 Carbon Additives 259 13.3 Examples of Flexible Batteries 260 13.4 Future Perspectives 266 14 Flexible and Large-area X-ray Detectors 271Gerwin Gelinck 14.1 Introduction 271 14.2 Direct and Indirect Detectors 272 14.3 Thin-film Photodiode Sensors for Indirect-conversion Detectors 273 14.3.1 Performance Parameters 273 14.3.2 Photodiode Materials on Plastic Substrates 275 14.3.2.1 Amorphous Silicon 275 14.3.2.2 Organic Semiconductor Materials 275 14.4 TFT Array 277 14.4.1 Pixel Architecture and Transistor Requirements 277 14.4.2 Flexible Transistor Arrays 278 14.5 Medical-grade Detector 282 14.6 Summary and Outlook 283 15 Interacting with Flexible Displays 287Darran R. Cairns and Anthony S. Weiss 15.1 Introduction 287 15.2 Touch Technologies in Non-Flexible Displays 287 15.2.1 Resistive Touch Sensors 287 15.2.2 4-Wire Resistive 288 15.2.3 5-Wire Resistive 289 15.2.4 Capacitive Sensing 290 15.2.5 Surface Capacitive 291 15.2.6 Projected Capacitive 291 15.2.7 Infrared Sensing 293 15.2.8 Surface Acoustic Wave 293 15.2.9 Bending Wave Technologies 294 15.3 Touch Technologies in Flexible Displays 294 15.4 Summary 299 16 Mechanical Durability of Inorganic Films on Flexible Substrates 301Yves Leterrier 16.1 Introduction 301 16.2 Flexible Display Materials 302 16.2.1 Property Contrast between Coating and...