#Super-Fast Pixels Could Make Smartphones Brighter and Longer-Lasting Displays account for between 45 and 70 percent of the total energy consumption in portable electronics.
A new kind of liquid crystal display (LCD) with pixels that switch much more quickly could give smartphones brighter screens
or make them last longer on a charge. The design uses new materials from Light Polymers, a startup based in South San francisco. In an LCD,
a layer of liquid crystal material in each pixel switches from one state to another to block the passage of specific colors of light.
The new design uses three backlights one red, one blue, and one green, that illuminate all of the pixels in the display in very rapid successionoo quickly for the eye to perceive.
The color of each pixel then depends on perfectly timing when it opens to let light through.
If it just open for when the blue light is on it looks blue. Opening it also for some red
or green would allow those colors to blend, to create different shades. The design is actually similar to one used for early televisions.
In a conventional LCD, pixels switch much too slowlyn the range of a couple of millisecondsor the technique to work.
Technology presented by Light Polymers at the 2014 Emerging Display Technologies conference in San jose this week could allow switching in less than 60 microseconds.
It involves using a new material that strongly anchors a kind of liquid crystal that switches pixels on and off very quickly.
The new designnown as a sequential displayould help LCDS close the energy efficiency gap with another type of display, the OLED.
OLEDS are used in some smartphones and TVS, but are more expensive to produce. Marc Mcconnaughey, CEO of Light Polymers, says the company materials are being evaluated by flat-panel display manufacturers.
They can be swapped in for materials currently used in manufacturing lines, which could make it easier for producers to switch over s
#Terahertz Chip Identifies Short Strands of DNA One of the more significant practical challenges currently occupying molecular biologists is to find better ways of identifying short strands of DNA.
Called oligonucleotides these strands of nucleotides are hugely useful in processes such as genetic testing forensics and DNA amplification.
But identifying the strands is laboured a somewhat business. Almost every detection method relies on fluorescent dyes
and markers that can be picked up by optical sensors providing a useful but indirect indication of the molecules that are present.
But molecular biologists would like a better system that measures the characteristics of the molecules involved
Indeed various research teams are working on such systems some with significant success. Today Andrey Chernev at St petersburg Academic University in Russia
Chernev and co aim to start by analysing the resonances of each of the monomer
The signatures from these should provide a kind of alphabet from which to work out the resonances of more complex polymers.
Chernev and co will have their work cut out to prove that their method is better than the others that are emerging.
http://arxiv. org/abs/1407.6520#DNA Detection By THZ Pumpin p
#IBM Chip Processes Data Similar to the Way Your Brain Does A new kind of computer chip,
unveiled by IBM today, takes design cues from the wrinkled outer layer of the human brain.
Though it is no match for a conventional microprocessor at crunching numbers, the chip consumes significantly less power,
and is suited vastly better to processing images, sound, and other sensory data. IBM Synapse chip processes information using a network of just over one million eurons,
which communicate with one another using electrical spikess actual neurons do. The chip uses the same basic components as today commercial chipsilicon transistors.
But its transistors are configured to mimic the behavior of both neurons and the connectionsynapsesetween them.
The Synapse chip breaks with a design known as the Von neumann architecture that has underpinned computer chips for decades.
Although researchers have been experimenting with chips modeled on brainsnown as neuromorphic chipsince the late 1980s,
until now all have been many times less complex, and not powerful enough to be practical (see hinking in Silicon.
Details of the chip were published today in the journal Science. The new chip is not yet a product,
but it is powerful enough to work on real-world problems. In a demonstration at IBM Almaden research center, MIT Technology Review saw one recognize cars, people,
and bicycles in video of a road intersection. A nearby laptop that had been programed to do the same task processed the footage 100 times slower than real time
and it consumed 100,000 times as much power as the IBM chip. IBM researchers are now experimenting with connecting multiple Synapse chips together,
and they hope to build a supercomputer using thousands. When data is fed into a Synapse chip it causes a stream of spikes,
and its neurons react with a storm of further spikes. The just over one million neurons on the chip are organized into 4, 096 identical blocks of 250,
an arrangement inspired by the structure of mammalian brains, which appear to be built out of repeating circuits of 100 to 250 neurons,
says Dharmendra Modha, chief scientist for brain-inspired computing at IBM. Programming the chip involves choosing
which neurons are connected, and how strongly they influence one another. To recognize cars in video, for example,
a programmer would work out the necessary settings on a simulated version of the chip, which would then be transferred over to the real thing.
In recent years, major breakthroughs in image analysis and speech recognition have come from using large, simulated neural networks to work on data (see eep Learning.
But those networks require giant clusters of conventional computers. As an example Google famous neural network capable of recognizing cat
and human faces required 1, 000 computers with 16 processors apiece (see elf-Taught Software. Although the new Synapse chip has more transistors than most desktop processors,
or any chip IBM has made ever, with over five billion, it consumes strikingly little power.
When running the traffic video recognition demo, it consumed just 63 milliwatts of power. Server chips with similar numbers of transistors consume tens of watts of powerround 10,000 times more.
The efficiency of conventional computers is limited because they store data and program instructions in a block of memory that separate from the processor that carries out instructions.
As the processor works through its instructions in a linear sequence it has to constantly shuttle information back and forth from the memory store bottleneck that slows things down and wastes energy.
IBM new chip doesn have separate memory and processing blocks, because its neurons and synapses intertwine the two functions.
And it doesn work on data in a linear sequence of operations; individual neurons simply fire
when the spikes they receive from other neurons cause them to. Horst Simon, the deputy director of Lawrence Berkeley National Lab and an expert in supercomputing, says that until now the industry has focused on tinkering with the Von neumann approach rather than replacing it,
for example by using multiple processors in parallel, or using graphics processors to speed up certain types of calculations.
The new chip ay be a historic development, he says. he very low power consumption and scalability of this architecture are really unique.
One downside is that IBM chip requires an entirely new approach to programming. Although the company announced a suite of tools geared toward writing code for its forthcoming chip last year (see BM Scientists Show Blueprints for Brainlike Computing,
even the best programmers find learning to work with the chip bruising, says Modha: t almost always a frustrating experience.
His team is working to create a library of ready-made blocks of code to make the process easier.
Asking the industry to adopt an entirely new kind of chip and way of coding may seem audacious.
But IBM may find a receptive audience because it is becoming clear that current computers won be able to deliver much more in the way of performance gains. his chip is coming at the right time,
says Simon
#Stacking Cells Could Make Solar as Cheap as Natural gas When experts talk about future solar cells they usually bring up exotic materials and physical phenomena.
In the short term however a much simpler approach stacking different semiconducting materials that collect different frequencies of light could provide nearly as much of an increase in efficiency as any radical new design.
And a new manufacturing technique could soon make this approach practical. The startup Semprius based in Durham North carolina says it can produce very efficient stacked solar cells quickly
and cheaply opening the door to efficiencies as high as 50 percent. Conventional solar cells convert less than 25 percent of the energy in sunlight into electricity.
Semprius has come up with three key innovations: a cheap fast way to stack cells a proprietary way to electrically connect cells
and a new kind of glue for holding the cells together. In its designs Semprius uses tiny individual solar cells each less than a millimeter across.
That reduces costs for cooling and also helps improve efficiency. The conventional way to stack semiconductors is to grow layers on top of each other.
But not all semiconductors can be combined this way because their crystalline structure doesn t allow it (see Adaptive Material Could Cut the Cost of Solar in Half).
Semprius grows semiconductor materials in the conventional way but also stacks several different combinations resulting in a solar panel that can capture more energy from sunlight.
Semprius has demonstrated cells made of three semiconductor materials stacked on top of a fourth solar cell that would not have been compatible otherwise.
It has made two versions of the device this year one with an efficiency of 43.9 percent
and the other using slightly different materials with an efficiency of 44.1 percent. In addition to being fast and precise the approach also makes it possible to reuse the expensive crystalline wafers that multijunction solar cells are grown on.
Eventually the company hopes to stack two multijunction devices for a total of five or six semiconductors with a very high performance beyond 50 percent efficiency says Scott Burroughs vice president of technology at Semprius.
He says the company hopes to achieve this in three to five years. The one catch is that the cells will be more costly than conventional ones.
Sarah Kurtz a principal scientist at the National Renewable energy Laboratory says costs won t come down until production happens at a large scale.
With economies of scale however such cells could improve the economics of solar power. At a scale of 80 to 100 megawatts a year of manufacturing capacity a cell with 50 percent efficiency would make it possible to reach costs of less than five cents per kilowatt-hour Burroughs says.
The U s. Energy Information Administration estimates that new natural-gas power plants will produce electricity at 6. 4 cents per kilowatt-hour r
#Mobile Gadgets That Connect to Wi-fi without a Battery A new breed of mobile wireless device lacks a battery or other energy storage,
but it can still send data over Wi-fi. These prototype gadgets, developed by researchers at the University of Washington,
get all the power they need by making use of the Wi-fi, TV, radio, and cellular signals that are already in the air.
The technology could free engineers to extend the tendrils of the Internet and computers into corners of the world they don currently reach.
Battery-free devices that can communicate could make it much cheaper and easier to widely deploy sensors inside homes to take control of heating and other services.
Smart thermostats on the market today, such as the Nest, are limited by the fact that they can sense temperature only in their immediate location.
Putting low-cost, Wi-fi-capable, and battery-free sensors behind couches and cabinets could provide the detailed data needed to make such thermostats more effective. ou could throw these things wherever you want
and never have to think about them again, says Shyam Gollakota, an assistant professor at the University of Washington who worked on the project.
The battery-free Wi-fi devices are an upgrade to a design the same group demonstrated last yearhose devices could only talk to other devices like themselves (see evices Connect with Borrowed TV Signals and Need No Power Source.
Versions were built that could power LEDS motion detectors, accelerometers, and touch-sensitive buttons. Adding Wi-fi capabilities makes the devices more practical.
Gollakota hopes to establish a company to commercialize the technology, which should also be applicable to other wireless protocols, such as Zigbee or Bluetooth,
that are used in compact devices without access to wired power sources, he says. A paper on the new devices will be presented at the ACM Sigcomm conference in Chicago in August.
Engineers have worked for decades on ways to generate power by harvesting radio signals from the air, a ubiquitous resource thanks to radio, TV
and cellular network transmitters. But although enough energy can be collected that way to run low-powered circuits,
the power required to actively transmit data is significantly higher. Harvesting ambient radio waves can collect on the order of tens of microwatts of power.
But sending data over Wi-fi requires at least tens of thousands of times more powerundreds of milliwatts at best
and typically around one watt of power, says Gollakota. The Washington researchers got around that challenge by finding a way to have the devices communicate without having to actively transmit.
Their devices send messages by scattering signals from other sourceshey recycle existing radio waves instead of expending energy to generate their own.
To send data to a smartphone for example, one of the new prototypes switches its antenna back and forth between modes that absorb
and reflect the signal from a nearby Wi-fi router. Software installed on the phone allows it to read that signal by observing the changing strength of the signal it detects from that same router as the battery-free device soaks some of it up.
The battery-free Wi-fi devices can harvest enough energy to receive and decode Wi-fi signals in the conventional way.
But they can detect the presence of the individual units, or ackets, that make up a Wi-fi transmission.
To send data to the battery-free device a conventional Wi-fi device sends a specific burst of packets that lets the receiving device know it should listen for a transmission.
The data is then is encoded in a stream of further packets with gaps interspersed between them.
Each packet signals a 1 and each gap a 0 of the digital message. Ranveer Chandra, a senior researcher in mobile computing at Microsoft Research, says the technology could help accelerate dreams of being able to deploy cheap,
networked devices that have been slow to arrive. iven the prevalence of Wi-fi, this provides a great way to get low-power Internet of things devices to communicate with a large swath of devices around us,
he says. RFID tags, which also lack batteries, are the closest technology in use today, says Chandra.
But they can only communicate with specialized reader devices, he says. The Washington approach fits better with existing infrastructure.
However, increasing the range of the system will be important for it to be widely useful, notes Chandra.
The upcoming paper on the technology reports a range of only 65 centimeters, which barely spans a small table, let alone a single room in a house.
Gollakota says that in recent, still unpublished experiments, the range has been extended to just over two meters,
and 10 meters and beyond should be possible d
#Using Your Ear to Track Your Heart If youe going to choose a place on the body to measure physical signals,
Steven Leboeuf says two places are far and away the best: the ear or the rear. Leboeuf knows it sounds like a joke,
but he not kidding. He the president and cofounder of Valencell, a company based in Raleigh, North carolina,
that developed and licenses technology it says can accurately track vital signs like heart rate, temperature,
and respiration rate from the same earbuds you use to listen to music. It does this with photoplethysmography,
or PPG, which measures changes in blood flow by shining a light on the skin
and measuring how it scatters off blood vessels (this is often done in hospitals with a device that fits over your fingertip).
At a time when many companies are betting on the wrist as the body part most likely to hold devices that measure activity and other signals from the body,
Valencell may seem like something of an outlier: the market research firm Canalys predicts that more than 17 million wristband gadgets will ship this year,
including eight million smart watches. And as Leboeuf readily admits, it a lot harder to build a device that goes in the ear than something that wraps around the arm.
The electronics need to fit into a smaller package, and rather than simply dealing with different wrist sizes youe got to contend with countless ear shapes,
as many earbud makers have found in the past. But the ear, Leboeuf maintains, is a much better source of data than the wrist
because it offers an area where blood flows neatly in and out, providing a much stronger signal and less noise.
Blood also flows to different parts of the ear at different rates, which can be used to measure different metrics.
And because we don move our ears as much as our arms, it can be easier to sort out intentional motions from unintentional ones.
Additionally, many of us are already wearing earbuds and headphones on and off throughout the day, and Leboeuf contends it not necessary to keep them on constantly to collect useful data.
With the right price and features, it could soon be easier to convince people to pick up a pair of earbuds that also happen to monitor your heart rate than a smart watch that does the same.
Valencell licenses its Performtek technology to companies for biometric measurement on many parts of the body (Scosche, for instance,
uses it in forearm-worn heart-rate monitors). But it also being used for a growing number of ear-worn devices,
including LG Heart rate Monitor Earphone and iriver iriveron Heart rate Monitoring Bluetooth Headset (available to consumers for $180 and $200, respectively) and a pair of earbuds from Intel,
which are still under development. And it could go far beyond health and fitness tracking, helping to monitor the condition of soldiers
and firefighters and changing the way we play video games. oul see games where your emotional state changes the character youe playing,
Leboeuf says. To make this kind of thing work, Performtek fits an optical emitter, photodetector, and accelerometer into an earbud.
The emitter shines an infrared light on a part of the ear between the concha and antitragusssentially, the lower part of the bowl of your ear,
just above your earlobend the photodetector picks up the light that scatters off nearby blood vessels.
The accelerometer, meanwhile, measures your movement. A digital signal processor (which can be housed inside or outside the earbud) analyzes the data,
removing oiselike skin movement or sunlight and extracting information like heart and respiration rates. With accelerometer and blood-flow data,
Leboeuf says, Valencell algorithms can also estimate things like the number of calories youe burned.
The data is sent then on to your smartphone. Leboeuf says Valencell technology has been validated by groups outside the company;
a paper he coauthored with researchers at Duke university medical school indicated that the company earbud sensor was able to accurately estimate total energy expenditure
and maximum oxygen consumption (the latter is referred often to as VO2 max) during exercise. Kevin Bowyer, chair of the University of Notre dame computer science and engineering department,
who has studied iris and ear biometrics, thinks it certainly possible to get good physiological measurements this way. think that
if you had the right, good-quality earbuds, you could actually do a lot in terms of reading biological signals related to the health of a person,
he says. Like Bluetooth headsets and some noise-cancelling headphones, the Performtek technology needs its own power source to work.
For earbuds currently on the market, that looks kind of clunky: the LG earbuds connect to a wearable clip that holds the battery and Bluetooth device,
while the iriver earbuds are attached to a sort of collar that sits on the neck and includes a battery and device controls.
But a pair of Performtek-using earbuds that Intel showed off this year at the International Consumer electronics Show in Las Vegaseant to be a reference design for manufacturersvoids this kind of bulk by harvesting power from the microphone jack.
Steve Holmes, who leads Intel New Devices Group, says this could also make it possible to add features like noise reduction.
Accelerometer data already being collected by the earbuds could even be used to create a sort of 3-D stereoscopic audio experience
without needing an additional battery or adding much cost i
#Adaptive Material Could Cut the Cost of Solar in Half A material with optical properties that change to help it capture more incoming sunlight could cut the cost of solar power in half, according to Glint Photonics,
a startup recently funded by the Advanced Research Projects Agency for Energy (ARPA-E). Glint adaptive material greatly reduces the cost of a tracking system used in some types of solar power.
It changes its reflectivity in response to heat from concentrated sunlight in a way that makes it possible capture light coming in at different angles throughout the day.
It well known that focusing sunlight makes it possible to use smaller cheaper solar cells. But this is usually done with lenses or mirrors,
which must be moved precisely as the sun advances across the sky to ensure that concentrated sunlight remains focused on the cells.
The equipment required for that and the large amount of steel and concrete needed to keep the apparatus steady makes the approach expensive.
Glint light concentrator has two parts. The first is an array of thin, inexpensive lenses that concentrate sunlight.
The second is a sheet of glass that serves to concentrate that light morep to 500 timess light gathered over its surface is concentrated at its edges.
The sheet of glass is covered with reflective materials on the front and the back that trap light inside the glass.
One of these sides features the new adaptive substance made by Glint. When a beam of concentrated light from the array of lenses hits the material, it heats up part of it,
causing that part to stop being reflective, which in turn allows light to enter the glass sheet.
The material remains reflective everywhere else, helping to trap that light inside the glassnd the light bounces around until it reaches the thin edge of the glass,
where a small solar cell is mounted to generate electricity. As the day goes on, the beam of light from the lenses moves and the material adapts,
compared to eight cents per kilowatt-hour for the best conventional solar panels. This month, the company received the first installments of a $2. 2 million grant from ARPA-E. The ARPA-E funding will allow the company to scale up from prototypes just 2. 5 centimeters across to make 30
-centimeter modules, nearly large enough for commercial operation. Howard Branz a program director at ARPA-E, says the main remaining challenge is increasing the amount of sunlight that makes it to the solar cells,
something that needs to be improved over the proof-of-concept device, in which some of the light is absorbed
or reflected en route to the solar cells r
#Cheap and Nearly Unbreakable Sapphire Screens Come into View This fall, rumor has it, Apple will start selling iphones with a sapphire screen that is just about impossible to scratch.
The supposed supplier of that sapphire, GT Advanced Technologies, can confirm as much. But this week the company showed
me a new manufacturing process that produces inexpensive sheets of sapphire roughly half as thick as a human hair,
making it possible to add a tough layer of sapphire to just about any smartphone or tablet screen relatively cheaply (see our Next Smartphone Screen May be made of Sapphire.
The manufacturing technology known as an ion accelerator, can make fine sheets of other costly materials,
so it could also lead to better and cheaper electronics and solar cells. Sapphire, or crystalline aluminum oxide, is made in nature
but can also be manufactured. It is second only to diamond in hardness, although incorrect processing can leave defects that make it brittle.
Because of its scratch-proof properties, it has long been used for making LEDS, sensors on missiles,
and the screens on some high-end phones that cost as much as $10, 000. But sapphire has been too expensive for widespread use.
A screen made entirely out of sapphire as the forthcoming iphone may be, remains five times as expensive as a regular one,
or $15 to $20 each. But laminating glass with sapphire could bring the cost down to $6, according to estimates by Eric Virey, an analyst for the market research firm Yole Développement.
Smartphone makers have taken long advantage of advances in glass production to make devices with stronger and more durable screens.
The most well-known of these screens is made from Corning Gorilla Glass, which is used in iphones.
But even Gorilla Glass is vulnerable to scratching and cracking, and replacing the glass is expensive.
The conventional approach to making sheets of sapphire is to saw a large crystal of the materialay 40 centimeters acrossnto wafers a few hundred micrometers thick.
These wafers can then be made thinner, but that requires more sawing, and then grinding the sapphire down,
which wastes huge amounts of sapphire. GT uses a different approach in its new machine,
which is the size of a concrete-mixing truck and operates in its labs in Danvers, Massachusetts.
The machine shoots hydrogen ions at a wafer of sapphire, implanting the ions to a depth of 26 micrometers.
The wafer can then be removed and heated up so that the hydrogen ions form hydrogen gas, which expands and causes a 26-micrometer-thick layer of sapphire to lift off.
Ted Smick vice president of equipment engineering at GT, says the next step is to engineer a system to automate the handling of sapphire wafers in a way that makes sapphire sheets at a fast rate.
He estimates that designing and implementing such a process will take about nine months
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