AMOLED also lends itself to flexible displays. In fact, some AMOLED-based flexible display innovations were showcased at the Consumer Electronics Show (CES) 2011. One example is the 0.27mm thick, 11.43cm (4.5-inch) flexible WVGA AMOLED display with a bending radius of less than 10 mm showcased by Samsung Mobile Display. However, larger flexible displays are still on the wish-list.
The technology that is giving AMOLED stiff competition in the smart phone space is Super-LCD (S-LCD). An upgrade of the time-tested LCD technology, this method of display is very power-efficient. It also overcomes some of the shortcomings of AMOLED, such as the high proportion of white pixels on the screen. Some manufacturers appear to prefer S-LCD because it is based on an already mature technology and does not face degradation and other inherent problems of OLEDs. S-LCD is mainly promoted by Sony. Apple’s Retina technology is also comparable to S-LCD.
[stextbox id=”info” caption=”Hot, hotter, hottest”]
Mature and popular. Multi-touch and high-definition displays, large and small; LED and OLED-backlit LCD displays of all sizes; full OLED displays in mobile devices; low-power, eco-friendly displays
Mature and gaining popularity. MEMS-powered mobile displays; 3D display technology; heat-stabilised polyester, PET and PEN films and patterned transparent conductor (PTC) films for flexible displays
Being fine-tuned. Large-format OLED displays; interactive displays
Emerging. Surface-emissive display technologies; shapeless, transparent, flexible, low-power and interactive displays for ubiquitous computing
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Surface-emissive display technology
Surface-conduction electron-emitter display or surface-emissive display (SED) is a technology that was in development alongside LCDs. However, when LCDs gained dominance some years ago, many companies wound down their SED development efforts. When many thought SED was a dead technology, companies like AU Optronics and Prysm Display picked up the threads and gave life to it again. Now it is picking up steam, especially since it is believed that current developments in nanotechnology can breathe new life into SEDs.
SED technology is especially suited for flat-panel televisions and other thin displays. It uses nanoscopic electron emitters to energise coloured phosphors and produce an image. An SED can be seen as a matrix of tiny cathode ray tubes, each forming a single sub pixel on the screen. These are grouped in threes, denoting red, green and blue (RGB) pixels. SEDs feature high contrast ratios, wide viewing angles, significantly low power consumption and very fast response times, all within a very thin form factor.
Prysm came out with a highly-discussed breakthrough in SEDs recently. Its new laser phosphor display (LPD) technology combines a phosphor panel, laser engine and laser processor. The result is a thin, large-format display that combines the low-power consumption and reliability of solidstate lasers with a surface-emissive screen.
“Fundamentally different from LED or LCD-based display technology, the LPD creates a modular, highly configurable display panel with brilliant image quality and the industry’s smallest environmental footprint. It uses rapid surface-scanning lasers controlled by advanced, high-speed inputs/outputs (I/Os) available on Xilinx field-programmable gate arrays (FPGAs) to excite phosphors, which, in turn, create brilliant, high-resolution pictures (with resolution as high as 4000 pixels) with very fast response,” explains Raju.
In addition to brilliant picture quality, LPD brings the advantage of energy efficiency by using lasers for turning the pixels on or off compared to a conventional display with an always-on backlight.
Mastakar explains, “The innovations in LPD were made possible by developments in the FPGA technology. Advanced high-speed I/Os which can work in the range of 1.4 Gbps, innovative manufacturing processes that merge the advantages of high performance and low power, and integrated architectural blocks like memory controllers and multi-gigabit SERDES in Xilinx FPGAs make system design easier.”
He adds, “LPD is one of the latest technologies in the SED category. It has the potential to replace backlit paper sign boards. It consumes less power, allows for true 180-degree viewing and provides incredible image quality. Quick-response liquid powder display (QR-LPD) is another promising technology targeted at ultra-low-power applications. A few other SED display technologies have emerged in the recent times, but these have not seen much traction in the market.”
Mems-based high-speed mobile displays
Apart from optics and materials, “micro-electromechanical systems (MEMS)-based high-speed mobile displays also form an important category of innovation in recent times,” feels Anup Tapadia, founder, TouchMagix Media.
The nature-inspired Mirasol display technology developed by Qualcomm is one example. This display is based on a reflective technology called Interfero metric Modulation (IMOD) with MEMS structures at its core. It is extremely low power yet highly reflective—the display can be seen even in direct sunlight.
Last year, Hitachi Display demonstrated an MEMS display prototype at CEATEC 2010. Built on Pixtronic’s micro shutter display technology, this device features very low power consumption—almost half that of LCD counterparts. It measured 6.3 cm (2.5 inches) diagonally, with a QVGA resolution of 320×240 pixels. An important feature of MEMS displays demonstrated by Hitachi is that they can operate in three modes—reflective, transparent and translucent. The transparent mode, for example, can be useful for ubiquitous computing or augmented reality applications.
It is hoped that the technology will be commercialised in the last quarter of this year.
Cool, smart displays
The development of displays that consume less power and emit less heat is an ongoing effort. In fact, this is considered to be one of the prerequisites for achieving long-term goals of ambient electronics and ubiquitous computing, where displays and computers will merge unobtrusively with our environment.
“Power consumption is a major issue for large displays (greater than 208 cm) and there is a concerted effort by government agencies and industry bodies to introduce regulation that will monitor the power consumed by existing and newer solutions. Definite progress is being made to rein in the power consumption on most of the existing technologies,” says Raju.
The use of LEDs and OLEDs is a major trend in terms of low-power efforts. Among the newer technologies in the industry, LPD offers a multiple reduction in power relative to other display technologies for the same brightness. Heating, ventilation and air-conditioning (HVAC) and power drops are the other issues to consider. Power consumed by the video controller chips is also a concern. It can be solved to some extent by adopting the latest FPGA chips that bring in power-efficient design features, such as Xilinx Artix 7. Qualcomm’s Mirasol display technology also represents a break-through in terms of power efficiency.
Very recently, Samsung Electronics acquired Liquavista—a spin-off of Philips Research Labs which develops ultra-low-power display technologies. Liquavista’s electrowetting technology, which operates in transmissive, reflective, transparent and transflective modes, enables creation of displays with bright, colourful images along with dramatically reduced power consumption. Offering more than twice the transmittance of LCD technology and operating at low frequencies, displays utilising electrowetting are expected to consume just 10 per cent of the battery power of existing display technologies.
Samsung plans to use electrowetting technology in its mobile products and expects great benefits in terms of power consumption and response times. In e-paper applications, for example, the response time of electrowetting displays will be more than 70 times faster than existing reflective displays, allowing colour video display. If and when Samsung brings out electrowetting-based devices, it will be another landmark in the low-power device market.
Displays that engage, interact
R&D efforts are contributing towards increasing the interactivity of displays—a prerequisite for realising the fantastic dreams of ubiquitous computing. Although real ubiquitous computing is still far away, the industry feels that audience recognition and engagement through interactive displays could be the next major milestone in display technology.
“We believe large displays would no longer be delivering one-way messages in the future. A user will be able to interact with these displays using multi-touch, gestures or even his mobile device,” says Tapadia.
A Pune-based company, TouchMagix is evolving as a major player in the international market for large-format, interactive, multi-touch displays. The company manufactures a new variety of interactive display solutions like Interactive Floor, Interactive Wall, Touch Table (Interactive Table), Touch Window and 3D Magix-Sense. TouchMagix currently exports products to more than 25 countries and serves clients like Nike, Intel, Reebok, Nokia, Castrol, Times Group, Infosys, Merck and Uniliver.
“I feel we are in for a bright future in irregularly shaped displays. In fact, in our company itself, we have an R&D team working on building interactivity for irregular shaped displays,” adds Tapadia.
It seems like the day of ubiquitous computing is not too far off with all these varied improvements in display technology. When the time comes, it will be nothing short of a revolution for it will change the way you interact with the computing systems.
The author is a technically-qualified freelance writer, editor and hands-on mom based in Singapore
