تکنولوژی جدید در رابطه با e-paper یا کاغذهای است که می تونن color image را نشون بدن!

 

 

 

28 April 2009—A new technology that uses ambient light and pigments used in commercial printing promises to make thin electronic displays that are as bright and vibrant as the pages of a glossy magazine, according to research reported this week in Nature Photonics.

Researchers at the University of Cincinnati’s Novel Devices Laboratory have developed what they call electrofluidic display technology over the past two years in collaboration with color experts from ink and pigments manufacturer Sun Chemical Corp. Sun Chemical also funded the work and has applied for a patent on the technology with the university.

An electrofluidic display is built from two sheets of plastic. Onto one sheet, mesa-like polymer structures are printed to form pixels. For each pixel, a hole taking up 5 to 10 percent of the pixel area (about 50 micrometers) is formed in the polymer and filled with a droplet of pigmented fluid. Surrounding the pixel is a trench cut into the polymer that contains air or oil. The pixels are topped by another sheet of plastic—this one containing a transparent electrode—leaving a 3-µm gap between it and the polymer pixel.

When there is no voltage between the plastic sheets, the pigment will stay inside the hole, essentially invisible to the naked eye. But when a voltage is applied, the pigment is pulled out of the hole and spread out along the glass, revealing its rich color to the viewer. The air or oil surrounding the pixel prevents the pigment in one pixel from spilling into another. Switching off the power lets the pigment recoil back into the hole.

If they meet their potential, electrofluidic displays ”would be the best technology there is,” says Russell J. Schwartz, vice president of color technology at Sun Chemical. ”It’s got durability, it has brightness of color, it has video speed, it has very low power consumption. So what am I missing?”

Michael Sinclair, a principal researcher working on displays at Microsoft who was not involved in the research, says electrofluidic displays are a novel idea. ”The fact that it is a reflective display is a big plus,” says Sinclair. ”Competing against the less than 10 percent efficiency of today’s LCD and their backlights, this technique ought to be a tremendous power-efficiency improvement.”

But Sinclair points out that researchers still need to work on a gray scale. And, he notes, if this new technology is to compete with the likes of the E Ink display in the Kindle, the Ohio engineers will have to find a way for the display to hold an image even when the power is off—a property called bistability.

Response time is another challenge. The current prototype has an average response time of just over 30 milliseconds, barely fast enough to display video. But the researchers say they have identified ways to improve the design that would theoretically decrease the response time to less than 1 ms.

Jason Heikenfeld, who led the research and is director of the Novel Devices Laboratory, says electronic paper would be only one of many possible applications. There is also potential for rollable displays, adaptive camouflage, and even cellphone cases that can change color on the fly, he says.

Heikenfeld says the reason this design works so well is that there is nothing between the viewer and the pigments except a pane of glass. ”You basically get to see the pigment without any losses, any polarizing filters. You actually get to look straight at the pigment,” he says.

Heikenfeld and some partners have formed a start-up company, Gamma-Dynamics, in Cincinnati, to develop electrofluidic technology. Prototypes may roll out in about three years, he says, followed by the commercialization of some of the simpler applications

تکنولوژی جدید این وسیله تکنولوژی است برای برقراری ارتباط با گیاهان

PHOTO: AgriHouse Inc.

BY Willie Jones // May 2009

4 May 2009—Although technology has benefited agriculture in a number of ways, there are some things that growers still do the old-fashioned way. Among them is putting their hands and other measuring devices in the dirt and judging, based on how moist the soil is, whether their crops need water and how much should be added.

But AgriHouse, an agricultural technology firm based in Berthoud, Colo., says it is marketing a new device that can eliminate irrigation guesswork by letting plants call growers via cellular networks to indicate when they need a drink. To be specific, the plants send text messages alerting growers if their water uptake is too little, too much, or just right.

AgriHouse’s leaf sensor clips onto a plant’s leaf and uses proprietary algorithms to translate its relative level of turgidity into a reading of its internal moisture content. Developed by the University of Colorado at Boulder for NASA’s human space missions and licensed exclusively by AgriHouse, the new sensors are set to be sold in early 2010.

The AgriHouse field station, a small, weatherproof electrical enclosure to which several of the centimeter-long turgidity sensors are wired, collects readings every few minutes, then sends packets of data over the cellular network to a secure, password-protected Web portal every few hours. The system can be programmed to activate an irrigation system or send an alert whenever the plant’s water-deficit stress levels fall outside a preset range.

Though too little or too much water can diminish yields, growers tend to err on the side of giving crops more water than they need rather than risk letting the crops dry up and wilt. AgriHouse claims their sensors could significantly lower the world’s freshwater usage by preventing plants from getting too much water at the wrong time. Commercial agriculture in the United States accounts for more than 60 percent of the freshwater consumed annually. This equates to roughly 129 billion liters per day, according to the U.S. Geological Survey. ”A savings of just 10 percent would be dramatic,” says Richard Stoner, founder and president of AgriHouse. Asked how big a savings the leaf sensor would likely yield, he notes that the amount varies by species of plant but that an annual reduction of 5 to 10 centimeters per hectare in applied water use would be feasible for most irrigated row crops.

Stoner says that for each circular 53-hectare field irrigated by a center pivot (a large rotating sprinkler system), the water savings realized by growers who clip a few of the sensors to their plants ”would be enough to supply as many as 50 U.S. homes annually.” Stoner notes that there are close to 200 000 center pivots in North America, ”so that’s a lot of freshwater that can be diverted to other uses.” He adds that for each of these center pivots, two to four sensors will provide enough redundancy to make an accurate assessment of what is transpiring in the fields.

On the flip side of the water-conservation coin is reduced energy use. You wouldn’t imagine that farming, which brings to mind pictures of idyllic meadows and rustic barns, is an energy-intensive business. But the energy required for water delivery—to pump water from wells, lakes, or reservoirs and distribute it across fields dotted with thirsty plants—accounts for half of a grower’s input costs, says Stoner. Under a typical center-pivot irrigation system, he adds, the water conserved by using AgriHouse’s leaf sensors could save a grower as much as US $4000 in annual pumping costs while substantially reducing carbon emissions. As for the sensors, they draw a miserly 50 milliwatts from the field station, which contains a lithium-ion battery pack that can store enough energy to run from the time seeds are sown in spring to when the crops are harvested in the fall