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A Paperless Society

Progress the Future


Solar cells made from strong and flexible "transparent paper" - CNF sheet material (Photo courtesy of Masaya Noki - Associate Professor at Osaka University.)

Further developments have been made in electronic paper, which is a medium that incorporates functions specific to the reading and writing of documents and is expected to replace paper in the future. Characteristically, the latest models developed by Japanese manufacturers have improved their information sharing functions and are able to activate company meetings, and transform school lectures into on-the-spot workshops in which all students can participate. Meanwhile, although paper is gradually being used less and less as a recording medium, research is being proactively developed in new industrial sectors where the paper-format is being changed to a new material; namely, the "future form of paper" envisioned by Japanese researchers.

The Thinnest & Lightest Electronic Paper

Electronic paper is able to save significant amounts of work in a whole series of document management processes; i.e. the printing of traditional paper materials, their distribution, revision, storage, recovery and discard. In December a leading Japanese electronics manufacturer released their latest device. It is A4 size and as well as being the world's thinnest (at 6.8mm) and lightest (at 358 grams), it is known for being easy to read and write with - but these are not its only important features. It also includes a great feature that offers a solution to significantly improve productivity in meetings and classes, and efficiency in learning, by allowing those who have this paper to easily and smoothly share information between them.



Left: “Digital Paper – DPT-S1” – electronic paper that you can read like normal paper. Its internal memory alone can store up to 2800 pages of PDF files and the touch pen that it comes with makes it easy to write too (Photo courtesy of Sony).
Right: The world's thinnest electronic paper, with a display equivalent to A4 size and a thickness of just 6.8mm. At 358 grams, it is also the lightest; lighter even than slightly smaller tablets (Photo courtesy of Sony)

For example, if these devices are used in a company meeting, not only can they efficiently distribute information to the participants over the wireless network, but they also instantly allow any memos that have been input to be revised and discussed, and so they are useful if, at a later date, you want to reconsider any opinions and ideas that you did not take on board at the time. If this technology were incorporated into university education, it would allow a brief test to be carried out during a lecture to identify any issues or queries facing the students there and then; thus enabling the contents of the lecture to reflect such issues/queries.

In addition, this technology can help to ensure thorough management of information, such as collecting in/destroying any distributed materials once they had been viewed. The new device is also highly rated as being easy to use and making the most of the electronic paper's strong points, with its specialized reading, writing and information sharing functions.

Power-Generating “Transparent Paper”


LEDs shining on circuitry imprinted on a 5x5cm sheet of CNF (Photo courtesy of Masaya Noki – Associate Professor Osaka University.)

As a paperless society gradually becomes a reality, the use of paper is spreading to other fields. There are high hopes for CNF (Cellulose Nano Fiber), a new, environmentally-friendly material made from the same raw materials as paper. In this fibrous material, the pulp is untangled and refined down to a diameter of 4-20 nanometers (nano: 1 part per billion). The solar cells using this new material that were developed by a research team at Osaka University in 2012 are a hot topic. These "transparent paper" type solar cells are a power generating mechanism. Light enters through a transparent sheet made of CNF and triggers a response in the thin layer of solar cell elements that overlay the sheet. Despite their very simple structure, in terms of organic, paper-based solar cells they recorded a world-best of 3% in their photoelectric conversion rate.


Pulp (on the left) is untangled and refined down to CNF (on the right). With a fineness of approximately 1/20,000 that of human hair, CNF has been very difficult to use in industrial processes (Photo courtesy of Oji Holdings.)

When making thin solar cells, the thin glass base panels traditionally used are highly heat resistant, but heavy and inflexible, while plastic film has disadvantage of forming a base panel that is susceptible to the heat and cannot be burned. On the other hand the "transparent paper" material maintains its integrity even when circuits are heated to temperatures of up to 200oC, and also has the advantage of not breaking when it is bent, meaning that you can fold it up and take it anywhere. Moreover, it should be possible to significantly reduce manufacturing costs if the fine wiring circuitry can be printed onto the base panel all at once.

Once this system is put into practical use, it will no doubt make our lives dramatically more convenient. We will be able to use curtains and clothes to generate power every day, and change specifications so that mobile phones no longer need charging and can be made as thin as a sheet of paper.

Fiber 5 Times as Strong as Steel


The world’s first transparent continuous sheet of CNF that has managed to be produced in lengths of several 100 meters (Photo courtesy of Oji Holdings.)

The material we call CNF makes up the cell walls of plants such as trees, and while it is 1/5th the weight of steel, it is 5 times as strong. Many countries are involved in research to try and utilize CNF in various fields; looking at how it could be added to cars to make the car body lighter and stronger etc. But it is Japan that has the largest number of patent applications by far in this area.

Meanwhile, it has been difficult to make long sheets of CNF for industrial use, but a leading Japanese paper manufacturer and chemical manufacturer have overcome this challenge through collaborative research. The two companies have merged their chemical processing, papermaking, and sheet processing technologies, and for the first time in the world they have managed to produce a continuous transparent sheet hundreds of meters long made from microfibers with a diameter of around 4 nano meters, which is close to the material's outside limit. And it seems they may be able to produce a more sophisticated sheet by incorporating antibacterial and deodorizing nano-particles into the gaps between the fibers.

With prospects for its mass production, CNF has made a major leap towards industrial production. And this is likely to encourage initiatives for its practical application in a variety of products from display components in organic EL and liquid crystal etc., to filters for filtering fine materials, to building and medical supplies etc.

(December 2013)

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