Plastic Logic demonstrates its fully organic flexible display with a smartwatch.
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Plastic Logic
Wrap-around smartphones and roll-up computer tablets could soon be coming to a store near you. A British electronics firm has created a plastic transistor. That could make possible a host of devices with flexible electronic displays.
To illustrate the possibilities, Plastic Logic showed off a flexible smartwatch with its new transistors at the Society for Information Display meeting last week in San Diego, Calif.
Like other digital displays, a flat plane of transistors sits underneath the light-up layer of the new smartwatch screen. Those transistors tell individual pixels on the plane above when and how much to light up. The arrangement of those pixels creates the pictures and text on a screen.
Both layers in the new smartwatch screen contain organic semiconductors. These are carbon-based materials that sometimes conduct electricity.
Organic light-emitting diodes, or OLEDs, form the display’s light-up layer. The OLEDs allow electricity to pass through organic semiconductors. Along the way, those materials release energy as light.
Engineers had already made some flexible OLEDs. The big advance for Plastic Logic’s display is the flexible plane of transistors.
Digital electronic displays need “at least one transistor behind each pixel to act as a switch to turn that pixel on and off,” explains Paul Cain at Plastic Logic. The physicist is marketing director for the company, which is based in Cambridge, England.
Thin plastic film transistors make it possible for Plastic Logic’s whole display to be flexible — and almost unbreakable.
Polymers are long chain molecules, often a building block of plastics. “What we’ve done is create a completely new kind of transistor that’s made out of plastic — out of polymers in solution,” explains Cain.
The transistors can be printed onto a surface, so that they coat it, using a process that takes place at room temperature. It is “a bit like spreading out cooked spaghetti onto a sheet,” notes Cain. The process makes very uniform layers.
Plastic transistors can make displays “virtually unbreakable,” he says. “You can put them in objects and not worry about dropping them in the way that you do with glass displays.” Goodbye, bulky cases for phones and tablet computers!
Displays also can be as thin as several cellophane sheets stacked atop one another. A whole mobile phone screen could wrap around the wrist like a thin piece of plastic. Other flexible gadgets become possible too.
Plastic Logic’s demo device “is elegant and impressive,” says Qibing Pei. “What is important here is that organic transistors can be made flexible over large areas.”
Pei works as a materials scientist and engineer at the University of California Los Angeles. Last year, he and his colleagues developed a stretchable OLED light that “is more flexible than skin.” They described their new development last fall in the journal Nature Photonics. Pei’s group also works on stretchable transistors.
Plastic Logic’s transistor sheets are able to bend with curves “well under 1 millimeter radius of curvature,” says Cain. For perspective, a sharp pencil point measures about 1 millimeter (or about 4 one-hundredths of an inch) across. What this means, Cain says, is that an OLED display effectively could be folded in half without damage.
Controlling distortion was a challenge in developing the new transistors. Plastic Logic prints its transistors as a series of layers. “We put down one pattern, and then we put down a spacer layer. And then we put down another pattern on top,” Cain explains.
Features of each pattern measure just a few micrometers (hundred-thousands of an inch). All patterns must line up precisely. If not, the pixels won’t display properly.
Flexible OLED devices like Plastic Logic’s sample smartwatch could be in stores within two to three years, says Cain. Other types of roll-up devices might go in your back pocket. A computer tablet could unfold from a small envelope size.
But that will still take a while because some challenges remain. For instance, those flexible displays will need some sort of coating or barrier to protect them from the damaging effects of moisture and air. “Barrier films currently available have limited flexibility,” Pei notes.
Cain agrees. But he also notes that other companies are working on that issue. Solving the barrier problem and other challenges will open up the possibility of many new types of electronic products.
“With plastic transistors, you can really unlock design features that just haven’t been possible” until now, Cain says.
To illustrate the possibilities, Plastic Logic showed off a flexible smartwatch with its new transistors at the Society for Information Display meeting last week in San Diego, Calif.
Like other digital displays, a flat plane of transistors sits underneath the light-up layer of the new smartwatch screen. Those transistors tell individual pixels on the plane above when and how much to light up. The arrangement of those pixels creates the pictures and text on a screen.
Both layers in the new smartwatch screen contain organic semiconductors. These are carbon-based materials that sometimes conduct electricity.
Organic light-emitting diodes, or OLEDs, form the display’s light-up layer. The OLEDs allow electricity to pass through organic semiconductors. Along the way, those materials release energy as light.
Engineers had already made some flexible OLEDs. The big advance for Plastic Logic’s display is the flexible plane of transistors.
Digital electronic displays need “at least one transistor behind each pixel to act as a switch to turn that pixel on and off,” explains Paul Cain at Plastic Logic. The physicist is marketing director for the company, which is based in Cambridge, England.
PLASTICLOGIC
Until now, commercially available transistors have been made on glass sheets. That’s because those earlier transistors were made from materials such as silicon. And making those transistors requires high temperatures.Polymers are long chain molecules, often a building block of plastics. “What we’ve done is create a completely new kind of transistor that’s made out of plastic — out of polymers in solution,” explains Cain.
The transistors can be printed onto a surface, so that they coat it, using a process that takes place at room temperature. It is “a bit like spreading out cooked spaghetti onto a sheet,” notes Cain. The process makes very uniform layers.
Plastic transistors can make displays “virtually unbreakable,” he says. “You can put them in objects and not worry about dropping them in the way that you do with glass displays.” Goodbye, bulky cases for phones and tablet computers!
Displays also can be as thin as several cellophane sheets stacked atop one another. A whole mobile phone screen could wrap around the wrist like a thin piece of plastic. Other flexible gadgets become possible too.
Plastic Logic’s demo device “is elegant and impressive,” says Qibing Pei. “What is important here is that organic transistors can be made flexible over large areas.”
Pei works as a materials scientist and engineer at the University of California Los Angeles. Last year, he and his colleagues developed a stretchable OLED light that “is more flexible than skin.” They described their new development last fall in the journal Nature Photonics. Pei’s group also works on stretchable transistors.
Plastic Logic’s transistor sheets are able to bend with curves “well under 1 millimeter radius of curvature,” says Cain. For perspective, a sharp pencil point measures about 1 millimeter (or about 4 one-hundredths of an inch) across. What this means, Cain says, is that an OLED display effectively could be folded in half without damage.
Controlling distortion was a challenge in developing the new transistors. Plastic Logic prints its transistors as a series of layers. “We put down one pattern, and then we put down a spacer layer. And then we put down another pattern on top,” Cain explains.
Features of each pattern measure just a few micrometers (hundred-thousands of an inch). All patterns must line up precisely. If not, the pixels won’t display properly.
Flexible OLED devices like Plastic Logic’s sample smartwatch could be in stores within two to three years, says Cain. Other types of roll-up devices might go in your back pocket. A computer tablet could unfold from a small envelope size.
But that will still take a while because some challenges remain. For instance, those flexible displays will need some sort of coating or barrier to protect them from the damaging effects of moisture and air. “Barrier films currently available have limited flexibility,” Pei notes.
Cain agrees. But he also notes that other companies are working on that issue. Solving the barrier problem and other challenges will open up the possibility of many new types of electronic products.
“With plastic transistors, you can really unlock design features that just haven’t been possible” until now, Cain says.
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