Monday, October 31, 2005

"DISPLAYS: Flexible displays, e-paper are around the corner"

Next year might be dubbed the year of the flexible, as roll-up displays and digital signage made of electronic paper debut. Ultrathin displays and e-paper took center stage at the Americas Display Engineering and Applications Conference here last week, with researchers reporting progress and predicting a 2006 deployment. Conference goers also heard of advances in LCD technology and in military-grade head-mounted displays. Nick Colaneri, associate director of the Flexible Display Center at Arizona State University in Tempe, outlined progress at that Army-funded center for the process development and pilot production of flexible backplanes and displays. Their target technology is organic transistors that can be fabricated at a cool 90°C, as well as other low-temperature formulations. The center will begin qualifying its second-generation TFT pilot line in 2006 and start prototyping with it in 2007. Flexible Display Center member companies are also providing facilities for research on electrophoretic ink for paperlike displays at E-Ink Corp. (Cambridge, Mass.), and on cholesteric liquid crystals for reflective and near-infrared displays at Kent Displays Inc. (Kent, Ohio). Unlike electrophoretic ink, which is monochromatic, cholesteric liquid crystals create full-color reflective displays without filters. SiPix Imaging Inc. (Fremont, Calif.), described progress toward commercial production of the company's full-color e-paper. SiPix's Microcup Electronic Paper is flexible, high-contrast and offers nearly a 180° field-of-view, but also is ultralow in power. Because it needs power only to change a pixel's color, it has zero standby power. Military head-mounted displays were described by Primordial (Saint Paul, Minn.). Its Primordial Soldier heads-up vision system applies tactical overlays, including annotations that label friend from foe on a soldier's HMD, perform automatic threat assessment and provide statistics on vulnerabilities. A revolutionary improvement for LCDs harnessing the human visual system was unveiled by Clairvoyante (Sebastopol, Calif.) The company's PenTile subpixel renderings reduce by one-third the number of pixels needed for a given resolution.

"NANOTECH: Nanotubes bend to the task of switching"

Cooperating to make an all-nanotube switch, electrical engineers from Cambridge University (England) and Samsung Electronics Co. Ltd. have circumvented the nano-to-micro interface. By lithographically seeding silicon wafers for nanotube growth of source, drain and gate electrodes, the EEs formed three-terminal switches that function like mechanical DRAM, dubbed a nanoelectromechanical system (NEMS) switch. The device can be used to switch routing connections on chips, as an alternative to on-chip fuses, for reconfiguration in a reversible manner and as an alternative to the silicon pillar structure now used as the base for capacitors in DRAM. The nanotubes for the source and drain grow from seeds to a precise length at right angles to the silicon wafer surface. The source nanotube is pinned to ground with photolithography while the drain is positively biased. The gate electrode, also a nanotube but shorter, switches the NEMS by introducing a positive voltage bias that repels the drain by electrostatic force. When the voltage on the gate surpasses a threshold, similar to the "on" gate voltage of a transistor, the drain nanotube bends and touches the oppositely charged source nanotube, thereby throwing the mechanical switch and allowing current to flow from source to drain. Van der Waals forces then provide hysteresis to "debounce" the switch, keeping it "on" until the gate voltage drops below an "off" threshold. To create a memory cell with the NEMS switch, the Cambridge researchers cooperated with Samsung to fabricate a complementary vertical capacitor structure to latch "on" states so that the gate voltage can be removed without switching the cell "off." By integrating the two into a vertical nanotube electromechanical switch and latch, the researchers said, ultrasmall DRAM memory cells could result. The University of Cambridge and Samsung team will reveal the tiny dimensions of their NEMS DRAM cell at the IEEE's International Electron Devices Meeting in December.

Monday, October 24, 2005

"OPTICS: Photons advance on two fronts"

Photons have electron and molecular properties that could be applied to such areas as sensors and fiber optics, recent experiments show. One group has discovered that solitons — self-sustaining waves of light — can form stable structures resembling molecules. Another team has extended photonic work on the Hall effect to phonons, which are quantized vibrations in a crystal lattice. The first discovery could enable fiber-optic telecommunications lines to double their capacity and eliminate the need for repeaters. The second result might enable Hall-effect sensors to be made from dielectric materials. France's Grenoble High Magnetic Field Laboratory reported observing the Hall effect in phonons. The work builds on a discovery several years ago by Grenoble researcher Geert Rikken that the Hall effect can be realized in photons — a surprising revelation because it had been thought that only charged particles, such as electrons, would respond in such a way to an external magnetic field. Now Rikken and Grenoble colleagues Cornelius Strohm and Peter Wyder have shown that phonons can likewise be harnessed to exhibit the Hall effect. The Hall effect is used widely in semiconductors for sensing and switching. A phonon-based version of the effect could lead to new operating modes for magneto-optical materials and devices that might in turn yield new sensor types.

"SECURITY: Lab-on-a-chip prepped to protect drinking water"

On Sept. 11, 2001, water resource managers across the United States got a wake-up call. In addition to desalinization projects and efforts to remove industrial waste, they now faced the possibility of intentional acts of poisoning public water. Sandia National Laboratories thinks it can help. To head off terrorist attacks on U.S. drinking water, Sandia has adapted its lab-on-a-chip, called the MicroChemLab, to real-time monitoring of public waterworks. The device aims to give water resource managers a real-time readout not only of poisons, but also of the naturally occurring toxins for which waterworks can now sample only randomly. The microfluidic-chip-based MicroChemLab prototype, fabricated with microelectromechanical systems, today resembles a 25-pound suitcase with two water collectors protruding from it. It is currently being tested in the Contra Costa Water District in California, collecting and analyzing water samples every 30 minutes and reporting the results in real-time over a wired link to researchers at Sandia. If testing is successful, future production versions of the MicroChemLab will be eligible for installation in any of the more than 300,000 U.S. public-supply water wells, 55,000 utilities and 120,000 rest stops and campgrounds.

Monday, October 17, 2005

"SOFTWARE: Steady pace takes Darpa race"

Slow but sure took the $2 million purse in the second Darpa Grand Challenge. Using what its developers called a "tortoise strategy," an autonomous Volkswagen Touareg named Stanley exploited artificial-intelligence techniques to cover 132 miles of Nevada desert in 6 hours and 53 minutes, for an average of just over 19 miles per hour. Second and third in the Oct. 8 race, sponsored by the Defense Advanced Research Projects Agency, went to a pair of Hummers from Carnegie Mellon University. Sandstorm trailed the leader by 11 minutes and H1ghlander by 21 minutes. Of the field of 23 autonomous ground vehicles that started the race before 2,000 spectators, only five crossed the finish line, and one of those exceeded Darpa's 10-hour time limit. Still, the results vastly improved on last year's Grand Challenge, when every entrant either stalled or crashed within seven miles. Last year's starting field all tried to outpace one another with horsepower. This year, the top three winners swore off horsepower in favor of reliability, ruggedization and smarts. "Our focus was reliability from the start, and in the end it was reliability that won the race," Bradski said. With two entries, Carnegie Mellon tried a tortoise-and-hare approach. H1ghlan-der, the "hare," had been favored to win, but ran into mechanical difficulties. "The pace we set for H1ghlander should have had it finishing 30 minutes ahead of [tortoise] Sandstorm. Unfortunately, H1ghlander had mechanical trouble that slowed down its pace," said professor William Whittaker, the CMU team leader. The brains of all three winning vehicles were identical, having been donated to Stanford and Carnegie Mellon by Intel, which permitted separate engineers to work with the rival teams. The computers used were six Pentium M processors, which were low power enough to run off the alternator in two of the three vehicles (H1ghlander had an auxiliary power generator supplied by Caterpillar Inc.). In-stead of laptops, the six Pentium M's were packaged as blades in a ruggedized platform designed to be earthquake proof (no spinning hard disks and a spike-resistant power supply). Each winning vehicle used one Intel 5091 chassis and six Intel MPCBL5525 processor blades. The Grand Challenge was conceived in 2002 by Darpa director Anthony Tether. The first race, in March 2004, offered a $1 million purse. When no one finished, the purse was upped to $2 million. So far, Darpa has reported spending about $20 million to organize and promote the Grand Challenge program. The agency has sponsored autonomous-vehicle research for more than a decade in hopes of meeting a Congressional mandate that one-third of all military vehicles be autonomous by 2015. Progress, however, has been so slow that Darpa decided to enlist outside help. Hence, the Grand Challenge.

"POWER SOURCES: Battery gets bionic charge"

Surgically implanted pacemakers only last for about five years before their nonrechargeable batteries — which draw current of less than a microamp — must be replaced. And devices like microstimulators, whose milliamp-current flows require bulky rechargeable batteries, must be reimplanted surgically far more often. Now a consortium of government, industry and academic organizations has developed a microstimulator with a tiny battery that can be recharged through the skin, enabling nonsurgical implantation for much longer periods of time. The microstimulator is used to bridge broken nerve connections resulting from Parkinson's, epilepsy and spinal chord injuries and other conditions. The bionic device also has a wireless transceiver that permits doctors to monitor the battery's state from outside the body. By building battery-monitoring and -charging functions into the external electronics, the bionic device can selectively monitor and direct the recharging of multiple microstimulators. The lithium-ion rechargeable battery was created with organic liquids, called organosilicon compounds, specifically for bionic implants. Organosilicons enable bionic batteries by using compounds composed of silicon and other natural materials, here designed to be electrolytes — the electricity-conducting liquid that stores charge in a battery. Today's microstimulators are so large that they have to be implanted and removed periodically to have their batteries replaced. These batteries are rechargeable through the skin, since nonrechargeables can't supply enough current, but they have be encapsulated to prevent them from leaking harmful chemicals. In contrast, the organosilicon-based bionic batteries contain no harmful chemicals and thus do not require a bulky case. In fact, the resulting implant is so small that it does not even require surgery to be inserted inside the body. The bionic battery was patented through the Wisconsin Alumni Research Foundation and licensed to a startup company, Polyron Inc.

"CHIPS: Surface-process study reveals transition region"

Understanding the surface process called wetting has become essential to the bottom-up assembly of atomically precise semiconductors as well as to the functioning of chips and boards. Now researchers at the Technion-Israel Institute of Technology (Haifa, Israel) have modified a transmission electron microscope (TEM) to reveal new details about wetting. At the atomic level, wetting is the movement of atoms at the interface between a solid and a liquid. Understanding the phenomenon is key to understanding crystal growth on silicon wafers, for soldering chips to boards, brazing flip-chips and controlling liquid flow through microfluidic chips. The aluminum-sapphire interface has been extensively studied worldwide in an effort to understand the high-temperature wetting processes, but the Technion group has uncovered evidence to back a hitherto unproven theory that a transition region exists at the interface. In this transition region, the precise atomic structure of the solid causes the liquid atoms likewise to become highly organized, resulting in layers of crystalline-like metal adjacent to the sapphire.

Monday, October 10, 2005

"SECURITY: Detector senses tiny sample of explosives"

While the increased threat from terrorism today has airports X-raying all luggage for weapons, there has been no fast, practical way for security personnel to scan baggage for the presence of bombs. Now, a Purdue University research team claims to have developed a sensor that is fast enough to detect tiny amounts of residue from explosives, using standard mass spectrometers outfitted with a special puff-and-sniff, two-nostril "nose." Professor R. Graham Cooks developed the method with the assistance of the doctoral candidates in his research group (, Ismael Cotte-Rodriguez, Zoltan Takats, Nari Talaty and Huanwen Chen. In the lab, mass spectrometers can easily detect trace residues of explosives brushed from the hand of someone loading a suitcase, thus determining whether a hazardous substance is likely to be inside. But either the suitcase must be swabbed or other time-consuming methods must be used to prepare a sample taken from its surface. In contrast, the Purdue researchers puff a gas mixture of ions onto the suitcase as it passes by, thereby using the ionic charge to eject molecules from the surface of the suitcase and into the two-nostril nose of the mass spectrometer. The technique, called desorption electrospray ionization (Desi), detects picogram (trillionths of a gram) traces of the explosives TNT, RDX, HMX and PETN, which are found within the plastic compositions of C-4, Semtex-H and Detasheet. An ionized solvent that specifically pinpoints the suspected explosives is sprayed on the suitcase. Two mass spectrometers used in tandem-the nostrils of the device's nose-reduce false alarms to negligible levels, according to Cooks, who claims the technique worked directly on a wide variety of surfaces without swabbing or pretreating them, including metal, plastic, paper and polymers.

Wednesday, October 05, 2005

"SENSORS: U.S. funding MRAM, night-vision sensor research"

A key U.S. military advantage has been its ability to fight at night. But current night-vision gear can't spot the enemy beyond 100 meters on moonlit nights.
Seeking to shed more light on the technology, the Defense Advanced Research Projects Agency's (Darpa) Microsystems Technology Office in investing in large infrared focal-plane arrays from Sensors Unlimited Inc. (Princeton, N.J.). The low-noise, dual-wavelength (both day- and night-vision) detector measures 1,280-by-1,024 pixels. It could help Darpa achieve its goal of seeing the enemy at 100 meters under "no-moon" conditions, including cloudy nights. No-moon focal-plane arrays could be available within three years. Separately, NVE Corp. ( Eden Prairie, Minn.) has received funding from the Office of Naval Research to continue development of it deep submicron vertical transport magnetoresistive RAM technology, which combines random access with nonvolatility. Sensors Unlimited's main business is short-wave infrared cameras using its proprietary indium gallium arsenide (InGaAs) process, which can transduce photons into electricity at dual wavelengths — both visible and shortwave infrared.' Requiring no cooling, the InGaAs focal-plane array is billed as providing high-resolution, passive night vision imaging using pixels oriented on a 15 micron pitch. The pixels are sensitive to wavelengths from 0.4 to 1.7 microns.' The company said it will take up to three years to complete the project. If it passes annual Darpa evaluations, the entire contract will be worth for more than $4.57 million.

Monday, October 03, 2005

"SENSORS: Microarrays, labs-on-chip enlist for early avian-virus diagnosis"

The scenario makes public-health officials sweat: Avian flu breaks out here in Portland. By day 24, there are 104 dead and 6,414 infected. By day 42, the death toll has risen to 846 or more and the infection level to 33,246. Had the city followed the vaccinate-and-quarantine regimen prescribed by the Models of Infectious Disease Agent Study (Midas), however, just 362 would be dead and 2,564 infected, with 34,559 citizens under quarantine. The quest to diagnose flu cases early, as the first step in containing an outbreak, has a new ally in an emerging breed of microarrays and labs-on-chip. In the face of dire warnings about bird flu from the World Health Organization, biochip makers are gearing up to provide custom microarrays to screen for avian flu strain H5N1 and its close cousins. The version built at the University of Colorado, Boulder, under contract with the National Institutes of Health, has just come out of testing at the Centers for Disease Control and Prevention (CDC), where a prototype microarray was exposed to a sample from a patient infected with avian flu. Meanwhile, STMicroelectronics says that its recently launched lab-on-chip, called In-Check, can be used to identify viruses like the flu. The nightmare scenario outlined for Portland is no fantasy. It comes straight from Midas' epidemic modeler, EpiSims, based on earlier simulations of 1.6 million Portland residents frequenting 180,000 locations where they might infect one another. EpiSims, designed to model smallpox outbreaks, has been retooled to model pandemic influenza of the bird-flu type. Another modeling tool comes from IBM Corp. According to James Kaufman, manager of Healthcare Informatics at IBM's Almaden Research Center (San Jose, Calif.), just a few changes in the parameters of its downloadable code ( could measure the use of flu chips in the fight against avian flu. The Java program, which IBM is offering free for noncommercial use, is called the Spatiotemporal Epidemiological Modeler (Stem). Users can tweak any number of parameters to try out their own ideas on containment.

"ROBOTICS: Bots prove their fitness as first responders"

The first responders surveying the devastation that Hurricane Katrina wrought in Louisiana and Mississippi were not all human. Autonomous vehicles also had a role, in an early indication of how robots might expedite the government's much-maligned response capability in future disasters. Vehicles that can go where humans cannot safely venture in the critical hours after a catastrophe have been developed at the center, which receives National Science Foundation funding, since the 1990s. The first application of center equipment for disaster response was the deployment of ground robots in Manhattan on the afternoon of Sept. 11, 2001, to search the rubble of the World Trade Center. After Katrina savaged the Gulf Coast in August, disaster responders deployed the center's unmanned aerial vehicles (UAVs) to search remote flooded areas in Mississippi. Within two hours of arriving on the scene, the UAVs had "cleared" a town by showing that no survivors were trapped — far faster than would have been possible by boat or manned helicopter, said Safety Security Rescue Research Center team member Robin Murphy, director of the University of South Florida's Center for Robot-Assisted Search and Rescue (CRASAR). Ground robots also aided in the Katrina response, searching structurally un-sound buildings in New Orleans. For such missions, CRASAR last year developed a sensor that enables a robot to determine whether a victim is dead or merely unconscious. Called a triage sensor by its commercial developers, Radiance Technologies Inc. (Huntsville, Ala.), the device can quickly screen for vital signs. On the battlefield, robots equipped with the sensor could be used to check downed soldiers, mitigating the risks to human medics. The fixed-wing UAV used in the Katrina response had both video feeds and a thermal imagery feed streaming from up to 1,000 feet away to provide overview scenes of the disaster area. The vehicle was launched manually by throwing it into the air and required a clear landing area of only about five car lengths. Also used was a miniature, electric T-Rex helicopter, courtesy of, that carried a streaming video camera. The hovering craft could scan areas from an altitude of less than 250 feet, its zoom lens inspecting rooftops and even peering in windows.

"SENSORS: Flu chips find clues in viral DNA"

A robotic inkjetlike nozzle places viral RNA on a microarray to populate it with more than 100 variations — bits and pieces of RNA called markers, that together identify the exact strain of the virus. Body fluids from the patient are amplified with a polymerase chain reaction, which makes thousands of copies for testing many simultaneous possibilities within the same microarray, and these are applied over the entire array. After that, the array is "developed" thermally and irradiated with a laser to induce fluorescence. Any matches will show up as glowing dots in a known location on the microarray, thus identifying the matching DNA sequence. Using a variety of known sequences, new viral DNA can usually be identified and sequenced in a few weeks to a month. SARS, for instance, was identified in this way in a coordinated worldwide effort of just a few weeks. After the virus is identified, microarrays can be stamped out like the microchips they are, and sent around the world for insertion into diagnostic gear, or readers.