Toppan Demonstrates Flexible Electronic Paper Driven by Oxide Semiconductor TFT

Apr 24, 2006
Toppan Demonstrates Flexible Electronic Paper Driven by Oxide Semiconductor TFT
Upper Left: Flexible TFT using Amorphous Oxide Semiconductor Upper Right: Prototype of Flexible Electronic Paper Display Bottom: Close-up of Prototype using Amorphous Oxide Semiconductor TFT (on glass substrate)

Toppan Printing Co., Ltd. has developed an amorphous oxide semiconductor thin film transistor (TFT) array and succeeded in driving an electrophoretic E Ink front panel laminate to fabricate a prototype flexible electronic paper display.

Today, TFT arrays for conventional Liquid Crystal Displays use amorphous silicon as the semiconductor and are fabricated on glass using a high temperature process.

Toppan has taken note of amorphous oxide semiconductor TFT developed by Professor Hosono of Tokyo Institute of Technology, because of its processability under room temperature and electrical properties that exceed those of amorphous silicon TFT.

Toppan processed these TFTs on a plastic substrate under room temperature and fabricated a flexible electronic paper display by combining it with an electrophoretic E Ink front plane laminate. This is the first time an E Ink electronic paper display has been driven by an oxide semiconductor TFT array.

This plastic substrate, amorphous oxide semiconductor TFT array is thinner, lighter and more robust than glass substrate TFTs and is flexible. Such mechanical properties bring next generation flexible displays closer to reality.

Toppan plans to develop flexible TFTs with goals to commercialize thin, lightweight and flexible displays such as electronic paper, starting with a practical prototype display in fiscal 2008. In parallel, we aim to introduce printing methods into the fabrication process of flexible TFTs for simplification and cost reduction.

Lightweight and flexible displays are considered a promising next generation product. Especially, with the recent developments in the field of electronic paper, led by electrophoretic displays, there is a heightened need to commercialize lightweight and robust flexible TFTs on plastic substrates.

Conventional flat panel displays, like LCDs are driven by TFTs on glass, processed at high temperature (mainly amorphous silicon TFT, fabricated at over 250 degrees centigrade). On the other hand, such a glass-based TFT array has many disadvantages for electronic paper because it is heavy, fragile and rigid (not flexible).

For this reason, many researchers are developing TFTs using plastic substrates, and because high temperature processes are not possible with plastic substrates, there is a lot of research & development for low or room temperature fabrication processes.

Toppan has been conducting research & development for lightweight and flexible TFTs, and one of our significant achievements was "All-Printed Organic Transistors," announced in November, 2003. This research showed that it was technically possible to fabricate a TFT array using organic semiconductor material and with printing processes only. Many researchers worldwide are working on organic TFT, but most of the printable organic semiconductor materials face technical challenges, including electrical properties of low mobility, small on/off ratio and short lifetime issue etc.

Then in the fall of 2004, researchers led by Professor Hosono of Tokyo Institute of Technology reported flexible TFTs using amorphous oxide semiconductor (a-InGaZnO) materials (Nomura et al, Nature 432, 488 (2004)). Toppan took note of this new approach and launched a research and development program using this amorphous oxide semiconductor material. This oxide semiconductor material is room temperature processable and has better electrical properties compared to conventional amorphous silicon semiconductors. It is also possible to apply printing processes for the TFT electrodes using printable metal pastes.

Source: Toppan

Explore further: Health care site flagged in Heartbleed review

add to favorites email to friend print save as pdf

Related Stories

Imec unveils fully organic imager for X-ray applications

Jun 13, 2013

At this week's International Image Sensor Workshop (IISW 2013, Snowbird, Utah, June 12-16 2013), imec and Holst Centre presented a large-area fully-organic photodetector array fabricated on a flexible substrate. ...

See-through transistor fabricated for future e-displays

Jul 27, 2007

Scientists have recently taken an important step toward the development of “see-through” flexible electronic displays by fabricating fully transparent, high-speed nanowire transistors. This piece of circuitry, ...

OLED Displays on Flexible Metallic Substrates

Jun 23, 2004

Universal Display Corporation, a leading developer of organic light emitting device (OLED)technologies for flat panel displays, lighting and other opto-electronic applications, and Palo Alto Research Center (PARC), a subsidiary ...

Recommended for you

Health care site flagged in Heartbleed review

8 hours ago

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...

Airbnb rental site raises $450 mn

9 hours ago

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Four questions about missing Malaysian plane answered

9 hours ago

Travelers at Asian airports have asked questions about the March 8 disappearance of Malaysia Airlines Flight 370 while en route from Kuala Lumpur to Beijing. Here are some of them, followed by answers.

Android gains in US, basic phones almost extinct

22 hours ago

The Google Android platform grabbed the majority of mobile phones in the US market in early 2014, as consumers all but abandoned non-smartphone handsets, a survey showed Friday.

User comments : 0

More news stories

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.

Health care site flagged in Heartbleed review

People with accounts on the enrollment website for President Barack Obama's signature health care law are being told to change their passwords following an administration-wide review of the government's vulnerability to the ...