Visible Progress

Stephen Atwood

Like many of you, I enjoy reading different industry periodicals because I never know where the next inspiration or clever idea may come from. One such example is the May 24th issue of EE Times magazine, which happened to come out right before SID's Display Week conference in Seattle. That week, EE Times featured an interesting article about Samsung's push into OLED TV, including a nice interview with SID President-Elect Brian Berkeley (worth a read if you have not seen it). But the reason I bring it up here is because of the cover story about Visible Light Communications (VLC), written by R. Colin Johnson. The principle is simple: If you have an LED-based visible-light source, you can modulate that source at a frequency much higher than the threshold of human flicker perception, and you can transmit digital information while the visible light appears to be solid to a human observer. Hence, you can light a room with LEDs and simultaneously transmit significant amounts of digital data such as streaming video, Internet, home automation, digital phone calls, or anything else imaginable – just by modulating those LEDs. In some cases, the light fixtures can even talk to each other along hallways and into connecting rooms, building an entire network without using any radio-frequency spectrum at all. Plus, the fact that light cannot penetrate walls makes your home network completely private from the outside. Ethernet or fiber would come into your house, go from the modem to the light controls, and then any room with a ceiling light is now Internet enabled.

The applications do not stop at the home, but can extend to almost anywhere artificial lighting is employed. One example cited is a ground-based locating system for car navigation that is updated by data sent from traffic lights in urban areas. The opportunities for commercial deployment are wide enough that the IEEE has even formed a standards effort, 802.15.7. A number of big-name companies are working on this technology, including Intel, Casio, NEC, Panasonic, Samsung, Sharp, and Toshiba. I am sure this is only a partial list. I am also sure there is a lot of backroom work going on that is not being talked about openly yet. One publically demonstrated application that was reported on earlier is the utilization of the LEDs in LCD backlights to send data from the display to another device. Samsung first showed this at Display Week 2009 in a large-area panel meant to illustrate a digital sign that could send data to your mobile phone when you approached the sign. The obvious application would be to send commercial advertising and targeted marketing to innocent bystanders through their mobile devices. This is the kind of thing that marketing people dream about in the wee hours of the morning and many consumers respond to like moths to a flame. I thought Samsung's demo was exceedingly clever and so did a lot of people who saw it.

Going beyond advertising, why not use the same mechanism to control active glasses worn by an observer to create more complex 3-D capabilities or to enhance the visual experience in other ways? You could even set up a two-way network with each pair of glasses and provide unique personalized viewing experiences for many observers of the same display. With data rates over 500 Mbits/sec already demonstrated in direct-lighting setups, there is enough bandwidth for many different applications that currently run over wired Ethernet today.

I think this is one of those paradigm-shifting technologies that will basically just appear one day and be everywhere the next. Traffic signals and all manner of outdoor advertising will be "data enabled" overnight. Just picture Times Square in New York City with all those lights and signs offering streaming content and personalized information to your handheld device. New buildings will be automatically designed with this technology in mind. The market for digital-data-capable LED light fixtures for homes could burst open before our eyes. The opportunity for widespread adoption at low cost with a clear value to consumers is so compelling that it could re-invigorate the entire home-automation industry. Imagine an almost endless array of wireless devices in one space with no radio-frequency conflicts or complicated setup issues. Full and unequalled privacy can be achieved within the walls of your home without you needing a master's degree in data-encryption technology. It will not be tomorrow, but I'm betting this will become one of those ubiquitous technologies such as mobile phones and microwaves. At some point, the thought of not being able to open your laptop under your desk lamp or point your iPhone at a billboard to get data will seem like being back in the dark ages.

Coming up in October will be our OLED technology issue, with a focus on architectural lighting. I am fairly sure the fast response time and wide range of power levels will enable OLED lighting to also support VLC and maybe create an interesting fabric of competition between discrete inorganic LEDs and OLED arrays in this marketplace.

Meanwhile, in our current issue, with help from our guest editor Dr. Shin-Tson Wu, Pegasus Professor at the College of Optics & Photonics, University of Central Florida, we celebrate the continuing innovation of LCD technology by looking at ongoing developments, including the state of the art for 3-D visual entertainment in the home. Now that flat-panel TVs, primarily LCD-based ones, are the standard for home entertainment, and with the clear success of 3-D cinema and its growing array of available content, it is more than obvious that 3-D television should be in strong demand as products become affordable. However, as author Jeong Hyun Kim points out in his Frontline Technology article "Evolving Technologies for LCD-Based 3-D Entertainment," there are still some meaningful shortcomings with regard to polarizing glasses and the resolution/cost tradeoffs associated with current approaches. Kim suggests a possible significant improvement over the status quo that clearly warrants further investigation.

Our next Frontline Technology feature also addresses 3-D, both glasses-based and autostereoscopic, as well as touch integration and other ongoing developments with LCDs. Authors Jenn Jia Su, Hsiang-lin Lin, and Alan Lien in their article, "Two New Technology Developments in the LCD Industry," provide a promising glimpse of the challenges and new developments in autostereoscopic LCDs, expressing their belief that the use of glasses is a short-term solution and that the final embodiment will be as natural as watching TV today, only three dimensional.

Earlier this year, we briefly described a JSID student paper on the development of the stencil method for field-sequential-color LCDs. This work was performed at the National Chiao Tung University (NCTU) in Hsinchu, Taiwan, by Assistant Professor Yi-Pai Huang and Professor Han-Ping D. Shieh, along with their very talented and innovative students. That paper was voted JSID's Best Student Paper for 2009. This month, Huang and Shieh return to share with us their broader views on the future possibilities of producing very low-power, full-color LCDs in their article "Eco-Display: An LCD-TV Powered by a Battery?"

Our fourth LCD feature this month is a look at the Display Marketplace for LCDs by frequent contributor and longtime industry colleague Paul Semenza of DisplaySearch. Paul examines the dilemma that LCD manufacturers face with continuing downward pressure on prices and the simultaneous need to fund never-ending expansions of their fabs. The answer of course is adding new technology, improving performance, and finding new ways to differentiate themselves to help sustain prices and margins. I think you will find his analysis, "Improvements in TFT-LCD Performance: Better Picture, Thinner, and Lower Power," very insightful and informative.

I really hope you enjoy this issue of Information Display. •