Advanced Display Technology
Description
This book provides a comprehensive and up-to-date guide to the AMOLED technologies and applications which have become industry standard in a range of devices, from small mobile displays to large televisions. Unlike other books on the topic, which cover the fundamentals, materials, processing, and manufacturing of OLEDs, this one-stop book discusses the core components, such as TFT backplanes, OLED materials and devices, and driving schematics together in one volume with chapters written by experts from leading international companies in the field of OLED materials and OLED TVs. It also examines emerging areas, such as micro-LEDs, displays using quantum dots, and AR & VR displays. Presenting the latest research trends as well as the basic principles of each topic, this book is intended for undergraduate and postgraduate students taking display-related courses, new researchers, and engineers in related fields.
Reviews / Votes
"This is a cutting-edge book on a hot topic. It is clearly a good reference for professionals in the field, especially for those with interests spanning from organic chemistry and solid-state physics all the way to systems issues." (Bogdan Hoanca, Optics & Photonics News, osa-opn.org, January 6, 2022)"This is a cutting-edge book on a hot topic. It is clearly a good reference for professionals in the field, especially for those with interests spanning from organic chemistry and solid-state physics all the way to systems issues." (Bogdan Hoanca, Optics & Photonics News, osa-opn.org, January 6, 2022)
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In Byeong Kang received his B.S. and M.S. degrees in Electronic Engineering from Hanyang University, Seoul, Korea, in 1989 and 1991, respectively. He also received his Ph.D. degree in Electronic Engineering from the University of South Australia in 1998. He subsequently joined LG Display, Korea, as a engineer in 1991, where he worked on the design and characterization of display for various applications such as IT, TV, and Mobile. He served as CTO, executive vice president, in LG Display from 2014 to 2020, leading technology research and development of future flat panel display such as TFT-LCD, AMOLED, and flexible display. In particular, he has led development of rollable OLED TV, transparent signage OLED, and 8K UHD OLED TV. He has published more than 30 co-authored international journal papers and 130 international conferences. He has also presented many talks at major display conference including keynote speech. He is a fellow of The Society for Information Display. Now, he is also a regular member of The National Academy of Engineering of Korea.
Chang Wook Han is the head of OLED device technology department as a chief research fellow and a vice president in LG Display, Korea. He obtained his B.S. and M.S. degrees in Material Science from Seoul National University, Korea, in 1987 and in 1989, respectively. He also received Ph.D. degree in Electrical Engineering from Seoul National University, in 2007. The title of his Ph.D. thesis was "a-Si:H TFT and pixel structure for AMOLED on flexible metal substrates". Since joining LG Display in 1990, he has worked on the device and process development on a-Si:H TFT backplanes for AMLCD. He has also focused on enhancing the performance of OLED device and developing new OLED panel structure since 1999. In particular, he has led several projects that have developed tandem white OLED and encapsulation technology for TV. He has experienced the successful application of these technologies to the world's first 55-inch OLED TV and transparent OLED products. His research achievements were recognized and he was presented the LG Group's R&D Grand Award, in 2013. He has also developed the innovated white OLED devices to meet the requirement for 4K and 8K OLED TV. Recently, he is in charge of developing TADF, blue phosphorescence, self-emitting QLED, and cultivating new OLED device for AR/VR micro-display. He has published more than 16 authored international journal papers and 30 international patents on flat panel display. He has published 4 authored chapters of book. He has also presented over 20 talks at major display conference including invited talks. He has served The Society for Information Display and International Meeting on Information Display conference as a program committee member on OLED.
Jae Kyeong Jeong received his B.S., M.S., and Ph.D. degrees in material science and engineering from Seoul National University, Seoul, Korea, in 1997, 1999, and 2002, respectively. In 2003, he was a postdoctoral researcher at the University of Illinois at Urbana-Champaign. In 2004, he joined Samsung Mobile Display Corp. as a senior engineer, where he had focused on the design and development of Si and amorphous IGZO TFTs for AMOLED display. In 2008, he successfully developed the world's largest 12.1" Oxide TFT-driven AMOLED display as a project leader. In 2009, he joined Inha University Incheon, Korea, as an assistant professor, where he had continued the oxide semiconductor and related field-effect transistors. Since September 2015, he is with the Department of Electronic Engineering at Hanyang University as a professor. His research group is interested in next-generation display electronics, CMOS TFTs for IoT, stretchable electronics, and emerging semiconductor devices. He has published more than 163 authored (or co-authored) international journal papers and 112 international patents. His total citation number and h-index are 21,498 and 56, respectively, according to the latest scholar google search. Also, he is currently an editorial board member of Scientific Reports and Journal of Information Display.
Content
- Chapter 1. Metal Oxide Thin-Film Transistor
Jae Kyeong Jeong (Professor at Hanyang University)
This review will give an overview of the recent progress in n-type oxide thin-film transistors (TFTs). The strategies toward high mobility will be addressed including the channel composition and structure, which is required to meet the demands of the ultra-high-resolution, large panel size and 3 dimensional visual effects as a megatrend of organic light emitting diodes and flexible displays. The device instability of oxide TFTs will be covered in details, which is critical for their implementation in the real product. The degradation mechanisms for the bias-thermal-stress and light illumination will be summarized including the carrier trapping/injection, defect creations such as oxygen vacancy, oxygen interstitial, hydrogen complex model. Finally, the self-aligned structure will be reviewed including the metallization process, copper interconnection for the AMOLED TV.
- Chapter 2. Pixel circuit of OLED display
Kee Chan Park (Professor at Konkuk University)Each pixel of OLED display needs an analog current source for uniform brightness over a whole display panel. Otherwise, mura due to the deviation of OLED characteristics or image sticking due to the irregular degradation of OLED device might be observed. A thin-film transistor (TFT) biased as subthreshold or saturation mode is used as the analog current source for OLED driving in each pixel. However, the characteristics of TFTs are not uniform at all. Therefore, another mura occurs due to the non-uniform current-voltage characteristics of the TFTs. Various circuit techniques have been proposed and employed in the OLED display product according to the applications. The operating principles of these circuit techniques will be explained, and the pros and cons of several representative circuit structures will be dealt with in this chapter.
- Chapter 3 . Phosphorescent OLEDs for power efficient displays
Michael S. Weaver and Tyler Fleetham (UDC)
In this chapter we will discuss phosphorescent OLED (PHOLED) materials and technologies. PHOLEDs are now used in virtually all OLED display products. We will discuss here the history of this technology, the inherent advantages of these materials and their future. The spin-orbit coupling is therefore enhanced, resulting in a mixing between the MLCT triplet and the singlet. To ensure high efficiency, particularly at high luminance levels, it is essential to minimize the triplet excited state lifetime. To achieve this, the MLCT triplet energy should be lower than that of the ligand. PHOLEDs incorporating phosphorescent organometallic compounds today have potential to exceed 40% EQE. Later we will discuss where next this technology can be even further improved.
- Chapter 4 . TADF and h yperfluorescence
Junji Adachi, Hisashi Okada (Kyulux)
TADF (thermally activated delayed fluorescence) is recognized the third generation of OLED emitting technology, which provides highly efficient emission without using any rare metal, such as iridium. TADF, which is designed small the energy gap between the singlet and triplet excited state, enables efficient spin up-conversion from triplet to singlet. As a result, highly efficient emission from singlet as high as 100% internal quantum efficiency was achieved without using rare metal, such as iridium. HyperfluorescenceT (HF) combines TADF and fluorescence to provide the ultimate solution for OLED display. TADF acts as excitons generator and transfers excitons to Fluorescence by Förster resonance energy transfer (FRET). Fluorescence molecule receives excitons and emits light as high as 100% internal quantum efficiency.
- Chapter 5. Solution-processible OLED material based on conjugated polymer technology
Takeshi Yamada (Sumitomo)
The development history, technology and current status of conjugated-polymer based soluble OLED material are reviewed. In addition, the application to display fabrication, comparison with other display technologies are also summarized and discussed.
- Chapter 6. Soluble small molecules for ink jet printed OLEDs - history, status and prospects
Remi Anemian (Merck)
Solution processing via Ink Jet Printing (IJP) is thought to be the next generation production technology due to its flexible scalability, in particular for large size displays, its higher material utilization rate and potential low costs. The following chapter will review the performance history from monochrome emission layers based on soluble small molecules to true RGB side-by-side printed architecture. Besides material properties and performances, process related requirements such as wetting, film uniformity and flatness will be discussed including implications on stack design. An outlook is given about upcoming trends to be adopted from vapor, as well as specific requirements regarding top emission device architecture and high pixel resolutions beyond 250ppi.
- Chapter 7 . Chemical m echanisms of i ntrinsic d egradation of e mitting l ayers in OLED d evices
Youngmin You (Professor at Ewha Womans University)
Short operation lifetime of organic light-emitting devices (OLEDs) remains as a major hurdle. The poor device longevity results from accumulations of defects during normal operation. This chapter summarizes the current knowledge about the chemical defects in OLEDs. Focus is on chemical mechanisms of the generation of defects. Unimolecular degradation from excitons or polarons is disclosed with the key examples. Chemical degradation by bimolecular processes, including excitonexciton annihilation (EEA) and excitonpolaron annihilation (EPA), are summarized. Strategies toward minimizing the bimolecular degradation are introduced. Finally, a recently identified bimolecular degradation by exciton-mediated electron transfer is overviewed.
- Chapter 8 . White OLED d evice t echnology and large-sized a pplications.
Chang Wook Han (LG Display)
Large-sized OLED TV has been commercialized as adopting tandem white OLED. Recently rollable and 8K OLED TV were also developed and open to the public. This chapter will cover key technologies including evaporation process, white OLED device and key technologies to realize OLED TV. Top emission white OLED for large-sized transparent display will also be reviewed. In the future, low power consumption is important due to environment problems. High-efficiency blue is most necessary to reduce power consumption. The latest research trends of high-efficiency blue OLED device such as phosphor-sensitized fluorescent (PSF) and hyper-fluorescent OLED.
- Chapter 9 . Encapsulation t echnology for f lexible OLEDs
Kyung Cheol Choi (Professor at KAIST)
Displays have evolved from rigid flat panels to flexible, rollable and foldable formats. Such changes in form-factor can provide improvements in consumer utility and convenience, including portability and ease of use. Developing a stable flexible display has attracted considerable attention for these reasons. But to realize the full potential of flexible OLEDs, they not only require enhanced characteristics to withstand rolling and folding, but a highly effective thin-film encapsulation barrier is also essential. This book chapter covers developments in encapsulation technologies, their structure designs, and materials for realizing flexible, rollable, and foldable OLEDs. Special focus is given to the existing hurdles to flexibility and how to overcome these limitations. Finally, further insights on the evolution of encapsulation technologies are discussed.
- Chapter 1 0 . Quantum d ot- e nabled d isplays
Charlie Hotz (Nanosys)This chapter will describe the structure, benefits and development status of each type of QD display, including the challenges each one faces relative to competitive technologies. A comparison of the emitter properties of QDs and alternative display emitters will be will also be reviewed.
- Chapter 1 1 . Quantum d ot based d isplays
Wan Ki Bae (Professor at Sungkyunkwan University)
Colloidal quantum dots (QDs) are few nanometer sized semiconductor nanocrystals whose electronic states are subject to change depending on their dimension. QDs have been of great interest as light-emitting materials in future displays owing to their superb optical properties such as near-unity photoluminescence quantum yield and narrow emission spectra, as well as their solution processability. The present chapter focuses on the emerging display technologies based on quantum dots. Specifically, this chapter covers the history of quantum dots for light-emitting applications, photophysical properties of quantum dots relevant to light-emitting applications, the state-of-the-art of and the perspectives on QD based display technologies.
- Chapter 12. Micro LED t echnology for d isplay a pplications
Dong Seon Lee (Professor at GIST)
In general, micro LEDs are defined as LEDs with a size of 100 µm or less, which are manufactured based on inorganic materials. Researches for developing micro-LEDs have been underway around the world as the demand for micro-miniaturized light sources increases, especially for display applications, but various problems are emerging in many ways. We introduce current research trend, issues, and efforts to overcome various problems of micro-LEDs as full-color light sources for display applications. We also briefly review newly presented technologies by research institutes and companies including their patents and products to examine their R&D strategy for micro-LEDs.
- Chapter 13. Display techniques for augmented reality and virtual reality
Byoungho Lee (Professor at Seoul National University)
Augmented reality (AR) and virtual reality (VR) have become important topics with the rapid growth of display technology and advances in communication technology. In this chapter we will review display technologies for implementing AR and VR. AR/VR display technologies can be categorized into glasses-type such as head-mounted display and window-type such as head-up display. We will discuss key issues for them and explain various technologies for implementing them such as diffractive optical elements, holographic optical elements, and light field technology. Especially, resolving the accommodation-vergence conflict is an important issue for 3D AR/VR to minimize observer's eye fatigue. We will explain this issue as well.