AR/VR, Digital Signage, Display Materials, Vehicular Displays, and Wearables Headline Display Week 2017 Technical Program in Los Angeles
A bumper crop of papers submitted to this year’s symposium ensures that the field will be broad as well as deep. Highlights include novel technologies like aerial displays, perovskites, full-windshield automotive head-up displays, and tunable microlens arrays, as well as practical advances in manufacturing and metrology that will help you do your job better. This is your once-a-year opportunity to find out what’s happening in the field of displays. The discoveries you’ll make at Display Week will inform your business plans for months and years to come.
by Jenny Donelan
This is a big year for Display Week. Nearly 700 papers were submitted to the Society for Information Display’s 2017 technical symposium. This is the highest number since 2011 (coincidentally or not, this was the last time Display Week took place in Los Angeles).
An impressive 30% of this year’s submissions were from China alone. Another 20% were from Korea, making one half of this year’s submissions from these two countries (approximately 75% of all papers are from the Asian nations of China, Korea, Taiwan, and Japan). “Display Week 2017 is shaping up to be one of the most technologically advanced and diverse symposiums we have hosted. It is a very exciting time to be in the display industry, anywhere around the world, and our speaker line-up aptly reflects this,” said Technical Program Chair Rashmi Rao at the paper selection meeting last winter in Seattle.
This year’s technical symposium runs from May 23 to 26, and will include 311 oral presentations and 240 poster presentations on a vast range of display topics. Obviously, that’s many more papers than any one person can take in during the four days of the program, but you can focus on the ones that are most important to you if you plan ahead by accessing the preliminary program online at http://displayweek.org/2017/Program/Symposium.aspx and also by reading this article, in which we point out some of the highlights. Last but not least: don’t forget to bring friends and colleagues along to cover what you can’t!
Papers at Display Week are organized into sessions by technical focus: Active-Matrix Devices, Emerging Applications, Applied Vision, Display Electronics, Display Manufacturing, Display Measurement, Display Systems, Emissive Displays, e-Paper and Flexible Displays, Lighting, Liquid-Crystal Technology, OLEDs, Touch and Interactive Displays, and Automotive/Vehicle Displays. Each session consists of three to five 20-minute presentations.
It’s worth noting that while the technical symposium is the heart and soul of Display Week, there are many other valuable events going on: the Sunday Short Courses and Display Metrology Workshops; the Monday Seminars; the Business, Investors, and Market Focus Conferences; the CMO Forum; and the Wednesday night Special Networking event at the Grammy Museum. New this year are a forum aptly titled “Women in Tech,” in which five distinguished women from technology fields will discuss their professional challenges and successes; and a special 30th Anniversary OLED Celebration, which includes talks from Ching Tang and Steve Van Slyke, the two researchers who delivered the first OLED paper at SID three decades ago. Visit www.display.org for a schedule.
Display Week 2017 Symposium at a Glance
Display Week 2017 Overview
The peer-reviewed papers chosen for presentation at Display Week represent the best work being done in display technology. Here are a few of the highlights from this year’s sessions. While it isn’t possible to mention every exciting development or worthwhile presentation in this space, we hope this list will serve to whet your appetite for what’s in store at the symposium.
Attendees take in one of hundreds of technical presentations at last year’s Display Week in San Francisco. The symposium is the heart and soul of Display Week.
Many Materials, Many Advances
Every year, SID creates areas of special focus that are designed to both reflect and encourage interest in specific areas of display technology. This year, these focus areas are AR/VR, Digital Signage, Display Materials and Processes, and Wearables. We’ll start with Display Materials and Processes, because there’s quite a bit going on here.
Thermally activated delayed fluorescence (TADF) emitters and perovskites are two “hot” new materials that are attracting a lot of attention, according to Ion Bita, co-chair for this year’s Display Materials and Processes program. TADF emitters have the potential to improve OLED performance, and perovskites are an emissive nanomaterial that may be used in ways similar to semiconductor QDs. Bita notes that while the investigated perovskites contain more lead than QDs (many of which contain cadmium), the Restriction of Hazardous Substances (RoHS) limits for lead content are higher than those for cadmium content. Cadmium-based QDs have faced some market challenges in terms of environmental regulations, and this may give perovskites an edge. Bita is also the guest editor for this issue of ID magazine, and has brought us articles on both TADF emitters and perovskites. Make sure you read them so you’re ahead of the curve before the show.
Speaking of QDs – they continue to be a popular research topic. It’s exciting to see a technology move from the emerging to the commercial category in just a few years. The paper “Key Challenges towards the Commercialization of Quantum-Dot LEDs” by Lei Quian of TCL Corporate Research will be useful for anyone wanting to get up to speed on QDs and QLEDs. Lei’s work covers performance, including efficiency and lifetime, as well as the development of printable QD inks (including ink-jet printing techniques), and blue QDs. To find out more about the environmental aspects of QDs, check out “Environmentally Friendly Quantum Dots for Display Applications” by Hyosook Jang of Samsung. This presentation describes the adoption of indium phosphide (Inp) based QDs as an alternative to cadmium-based ones.
Two other intriguing materials are carbon nanotubes and zinc-oxide nanorods. You can find out more about them in the presentations “Printed Carbon-Nanotube TFTs and Their Application in OLED Backplane Circuits” by Jianwen Zhao at the Chinese Academy of Sciences and “ZnO Nanorod Array Fabricated on Conductive and Transparent Gallium-Doped ZnO substrates for Sensing Applications in Displays” by Chaoyang Li of the Kochi University of Technology, respectively.
According to Frank Yan, chairman of the Emissive Displays subcommittee, research interest is strong in quantum-dot light-emitting diode (QLED) and micro-LED materials. Micro-LED papers increased from 3 to 7 this year over last, and emissive sessions expanded from 5 to 7. Submissions from China accounted for about half those papers. (Yan mentioned that the technical committee in China organized the International Conference on Display Technology [ICDT], encouraging scientists to submit papers to ICDT as well as to Display Week, which had a positive effect on both quantity and quality.) In terms of the emissive papers from all over the world, says Yan, “The overall quality was very high. We had to reject papers of reasonable quality this year that would have been selected in previous years.”
Michael Weaver, chair of the OLEDs subcommittee, also mentioned TADF emitters as a popular topic, because it is a competing technology compared to phosphors as an OLED emitter material. Another trend for OLEDs that Weaver points to is digital cinema. A recommended OLED paper in this area is “Curved Kawara-Type Multidisplay Combined with an OLED Device for BT.2020 Color Gamut” by Daiki Nakamura of SEL, which describes a multidisplay capable of displaying a seamless image with few visible joints. The OLED display achieves an area ratio of 106% to the BT.2020 color gamut in the u'v' chromaticity diagram.
Augmented reality and virtual reality devices, especially the head-mounted variety, frequently show up on the pages of mainstream media, but the devices themselves aren’t in the mainstream in terms of usage. The challenge of making comfortable, useful devices that will take advantage of “killer apps” yet to come is also an opportunity for display makers. No further indication of such interest is needed than the Society’s selection of Clay Bavor, vice president of virtual reality for Google, as one of the keynote speakers who will kick off Display Week. Google’s best-known foray into this area was Google Glass, but it now makes the affordable ($15) Google Cardboard and the comfortable (fabric-covered) Daydream viewers. Bavor is sure to have lots to say about the state of the art and the future of VR and how display companies can be part of it.
The technical symposium will offer several AR/VR sessions with a large number of invited papers, including “Liquid Crystal Lenses in Augmented Reality” by Yi-Hsin Lin from National Chiao Tung University and “A Switchable Light-Field Display for Mobile Applications” by David Fattal of LEIA. (ID magazine interviewed Fattal in the January/February 2017 issue.) There is also an entire session dedicated to Light-Field Displays for AR and VR that is sure to offer a lot of insights into the promising territory of light fields.
A Large Display by Any Other Name...
All digital signs are electronic displays, but not all electronic displays are digital signs. The distinction probably isn’t terribly important outside of Display Week, but for the purposes of categorizing papers for the symposium, the technical committees decided to designate displays larger than 120 inches as digital signage, says Gary Feather, chair of this year’s digital signage focus initiative.
“LCD is probably the major digital signage technology right now,” says Feather. One popular trend is reducing the bezel so as to make display “walls” that can be configured to look like mirrors, or actual walls, or whatever kind of backdrop might be required.
Another trend is LEDs for digital cinema that would incorporate Dolby vision at 4,000 nits. “These would be ultra fine pitch, and fine pitch is the important thing,” says Feather. (For more about high-resolution LED signs, see Feather’s article, “Elemental Evolution of Digital-Signage Components,” in the January/February 2016 issue of ID magazine.)
Find out more about both trends from the papers “Development of a Zero-Bezel Display Utilizing a Waveguide Image-Transformation Element” by Sejin Lee of LG Display Co., Ltd. and “Fine-Pitch Image Quality on LED Video Screens” by Jorge Perez Bravo of NanoLumens.
Exploring the High Dynamic Range
“The biggest trend in Applied Vision is HDR [high dynamic range],” says David Hoffman, subcommittee chair for Applied Vision. “We have a whole session on that. And we have an invited speaker from a [film] studio, Universal Pictures – we don’t get studio people to speak to us very often. I think it’s going to be really interesting.” That paper, “Qualitative Exploration of HDR Display Performance,” by Bill Mandel of Universal Pictures, considers HDR content in relation to HDR display capability. The author presents test patterns and related tools that explore contrast and saturation across HDR tone ranges, and argues for further exploration of HDR techniques in conjunction with human vision factors to continually improve the viewing experience.
HDR cropped up in Display Electronics as well, according to subcommittee chair Wei Yao, who noted there were quite a few papers on the topic – in fact there is an entire session devoted to HDR and image processing. “This is a ‘soft’ area, which is unusual for display electronics,” says Yao, meaning that Display Electronics does not usually address aesthetics. “This is about processing the data, making it look nice for consumers who buy the TVs.”
The other trend in Display Electronics – driving circuits for OLEDs – Yao describes as “less soft” and indicative of industry-wide interest in OLEDs.
Displays from Head to Toe
Currently, two of the hot areas for wearables research are displays and supporting electronics that can be worn on the body in the form of clothing or sensors, and display systems that are worn on the head, such as VR goggles.
The former category includes efforts to make stretchable and flexible systems that can ultimately mimic fabrics and protective clothing. Most of the stretchability papers have to do with the underlying electronics that allow the stretchability, notes Bill Cummings, co-chair of the Wearables program. He points to “Smart Fabrics Functionalized by Liquid Crystals” by John West at Kent State University as an especially interesting, out-of-the ordinary paper. It describes liquid-crystal functionalized smart fabrics fabricated by gas jet- or electro-spinning. According to the authors, “These fabrics retain all the stimuli-responsive properties of liquid crystals. Because they are flexible, self-supporting and have large
surface-area-to-volume ratios, [they] are ideally suited for an array of sensing applications.”
The other aspect of wearables is what Cummings describes as “things that attach to your head.” These displays have to get better, he says. “People don’t really want to put things on their heads. And they don’t know what to do with it [head-mounted technology].” The need for head-mounted displays and the quality of the head-mounted displays must come together, he continues.
In terms of the latter, a necessity is a very high resolution display near to your eyes, and companies are working toward that goal. “We’re excited to see the activity at this conference,” he says. “What we’re seeing is a merger of activity in microdisplays among established companies, start-ups, and university research labs. And when there’s a lot of activity, there’s a lot of innovation.”
There’s also an entire session on micro-LED displays, including a good overview of this technology, the invited paper “Nitride Microdisplays and Micro-LED Displays,” by Hongxing Jiang of Texas Tech University, which will discuss development, applications, and future possibilities.
Displays on Wheels
Vehicle designs incorporate ever-increasing numbers of displays for both information and entertainment purposes, and this is a welcome trend for display makers. According to Karl-heinz Blankenbach, chair of the Automotive/Vehicle Subcommittee, there is a trend toward larger and curved displays for infotainment as the industry looks toward autonomous driving. “There’s a notion of cars as a third living space,” says Blankenbach. In addition, high-concept interior and exterior lighting (often using LEDs) is increasing, with the latter even beginning to serve as branding by creating a uniquely recognizable look for the vehicle.
If you’d like a big-picture view of what’s happening in vehicles, check out “How the Mobility of Tomorrow Influences the Technologies of Today” by Nadine Langguth of Merck KGaA. This paper considers autonomous driving, the connected car, urbanization, car sharing, transportation on demand, and many other use trends that will affect not only drivers but display makers.
Automotive topics, including human-machine interface (HMI), are covered in several sessions. An entire session is devoted to automotive HMIs, with four invited papers by prominent authors.
Making and Measuring Displays
Display Manufacturing received the largest number of papers in at least five years, according to subcommittee chair Dr. Tian Xiao. Hot topics include the application of emerging materials such as graphene in displays, and LTPS and oxide TFT manufacturing technologies that are compatible with flexible/bendable displays. The topic of oxide TFT is not new, says Xiao. “But the ultimate goal is to make the manufacturing cost of oxide TFT on par with that of amorphous silicon TFT, and the race is on to make that happen!”
Another trend he sees is high resolution for OLEDs. There are many papers on how to manufacture OLED displays with very high-ppi values, Xiao says, adding that this is partially driven by AR/VR, where such high resolution is needed on very small display formats.
Another notable paper in display manufacturing combines both metrology and manufacturing disciplines. “Applied Materials [the author] is really helping the industry to improve the yield for high-resolution frontplanes and backplanes,” says Xiao. “It involves using inline SEM [scanning electron microscope] technology on large panels.” The invited paper is “Inline Electron-Beam-Review (EBR) Accelerates Yield Ramp-Up of Advanced Displays” by Xuena Zhang of Applied Materials.
The big news in Display Measurement, according to subcommittee chair Tom Fiske, is AR/VR and the new ICDM standard. There is an entire session on metrics for AR/VR. “People are proposing several different methods for NTE [near to eye] display measurements. These measurement systems, in some cases, attempt to measure optical performance parameters in ways that mimic what the human eye sees – or at least in ways that are relevant to the human visual system.”
Not to be missed is an overview of the progress of the revised ICDM display measurements standard, which will include new methods of optical metrology for resolution, HDR, AR/VR, curved displays, and more. This presentation, by Joe Miseli of JVM Research, is called “Progress Toward the ICDM2 Display Measurements Standard.” Says Fiske, “This is a very significant publication. A lot of companies are involved and care deeply about it.”
The following is a list of a few more notable papers (there are many more than can be named here) from various areas of the technical program:
How Lighting May Affect Your Health — “Biological Effects of Light: Can Self-luminous Displays Play a Role?” by Mariana Figueiro of the Lighting Research Center at Rensselaer Polytechnic Institute
“This is a look at the impact of lighting on health,” says Lighting Subcommittee Chair Marina Kondakova. “The author describes the effects of lighting, especially blue light, on circadian rhythms.” The paper considers displays that produce more blue light in daytime and more amber light at night. This “tunable” lighting is being used in hospitals and in Alzheimer’s facilities.
Investigating OLED Touch — “A Novel Touch-Control Method with Partial Scanning for LC, OLED, and Hybrid Displays Using an Oxide Semiconductor” by Kei Takahashi of Semiconductor Energy Laboratory Co., Ltd.
“We have a great OLED touch session,” says subcommittee chair Jeff Han. This paper is one of three in that special session.
Illumination Decisions — “Lasers, Lamps, or Phosphors – Choices for the Future of Digital Cinema” by Michael Perkins of Christie Digital Systems
The first generation of digital cinema projectors are now being deployed into the majority of movie theaters around the world. The illumination technology of choice for that first generation was Xenon lamps. Now that laser and laser-phosphor are mainstream illumination technologies, cinema projection engineers have a whole new set of decisions to make.
A Display You Can Dive Into — “An Aerial Display: Passing through a Floating Image Formed by Retro-Reflective Reimaging” by Hidetsugu Suginohara of Mitsubishi Electric Corp.
The authors have developed a 56-in. floating image that you can “dive” into. This is one of three papers in a special Aerial Displays session with Display Systems.
Better Surgery Through Augmented Reality — “Augmented-Reality Training System for Endoscopic Surgery” by Rong Wang at the Chinese Academy of Sciences
The authors propose a 3D augmented reality (AR) system for perception training on the ablation of a tumor inside the kidney. The system consists of region-based visual tracking for localizing the kidney and tumor and a 3D display for visualizing AR results. They also integrate a virtual instrument in the system.
A Microlens Array for Surgeons — “Wavelength-Independent Electrically Tunable Microlens Array with a Chiral Nematic Liquid Crystal” by Kai-Han Chang with the Liquid Crystal Institute at Kent State University
This is a late-news paper that describes a liquid-crystal microlens array with low operating voltage and wavelength-independent, electrically tunable focal length, qualities that make it suitable for full-color 3D microscopy and endoscopy applications.
Getting LCDs Ready for the Spotlight — “Can LCDs Outperform OLED Displays in Motion-Picture Response Time?” by Shin-Tson Wu of the University of Central Florida
The author of this invited paper describes some metrics that would improve LCD motion-picture response time.
Super-stretchy LEDs — “Ultrathin Stretchable Oxide Thin Film Transistor and Active Matrix Organic Light-emitting Diode Displays” by Seong-Deok Ahn of ETRI
The authors demonstrate ultrathin, stretchable oxide thin-film transistor and active-matrix organic light-emitting diode displays that can be operated as free-standing ultrathin films under 30% strain.
Introducing an 8K BT.2020 AMOLED — “An 8.34-in. 1058-ppi 8K x 4K Flexible OLED Display” by Tomoya Aoyama of Semiconductor Energy Laboratory Co., Ltd.
By combining an OLED device with a color filter and a specially designed top emission structure, the authors successfully fabricated a full-specification 8K AMOLED panel with the BT.2020 color gamut.
High Gamut Automotive Displays — “Quantum-Dot-Based Wide-Color-Gamut TFT-LCDs for Automotive Applications” by Rashmi Rao and Elijah Auger of Harman Inc.
This paper will discuss the details of manufacturing a wide-color gamut LCD-TFT display using quantum dot film, and the testing procedures used to qualify such a display for automotive applications. •