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Next-gen displays

An extremely low power, easy-on-the-eye screen using an electronic paper display can be used in a wide array of applications, writes Nivedan Prakash

An Electronic Paper Display (EPD) technology has been a long time coming. The idea of e-paper, a data display that looks and works like a sheet of paper has been around for decades. In theory, such a screen could be ‘printed’ electronically, would hold its contents without consuming power, could be viewed using reflected light (rather than the backlight required for LCD screens), and could be ‘erased’ and ‘rewritten’ as often as desired.

An EPD display possesses a paper-like high contrast appearance, ultra-low power consumption, and a thin, light form. It gives the viewer the experience of reading from paper, while having the power of updatable information.

EPDs are ideal for many consumer and industrial applications where the reading experience and range of lighting and viewing angles are of the utmost importance. You can use transportation signage in myriad locations where it is otherwise impractical due to the incidence of direct sunlight or viewing angle. e-Books that strained the eye with their emissive light can now give the reader the true book-like experience. Cell phone screens that you had to shade and tilt continuously for a glimpse of the numbers can now have high contrast and high brightness in the widest of lighting conditions. EPDs empower product designers to use their imagination in new ways.

Some of the applications for this technology would be in the mobile information market, e-textbooks, e-newspapers, e-magazines and e-books. Other mobile applications include Web browsers delivering the best ‘out of home’ experience where the user can literally leave the power cord at home as the display will last for a few days on a single battery charge. GPS devices, data collectors for inventory logistics applications, marine applications, and secondary displays on laptops, e-notepads, medical and industrial devices along with applications in the signage industry represent applications for higher information content displays.

“Electronic paper technology is also used in lower information or segmented display applications such as electronic shelf labels , point of purchase signs, mobile phones, radios, portable audio devices, wrist watches, USB memory sticks, glucose meters, smart cards and weighing scales, to mention a few,” said Sriram Peruvemba, Vice-president, Marketing, E Ink.

Adding to it, Ashwin Khorana, Senior Vice-president, Software Solutions, Scope International, said, “Applications include e-book readers capable of displaying digital versions of books and e-paper magazines, electronic pricing labels in retail shops, time tables at bus stations, and electronic billboards. At the same time, electronic paper should not be confused with digital paper, which is a pad to create handwritten digital documents with a digital pen.”

Electronic-ink in use

Electronic ink that carries a charge that updates it through electronics enables EPD technology. Electronic ink is ideally suited for EPDs as it is a reflective technology, which requires no front or backlight, is viewable under a wide range of lighting conditions, including direct sunlight, and requires no power to maintain an image.

Electronic ink is a proprietary material and when processed into a film you can integrate it in electronic displays. Although revolutionary in concept, electronic ink is a straightforward fusion of chemistry, physics and electronics to create this new material. The principal components of electronic ink are millions of tiny microcapsules, about the diameter of a human hair. In one incarnation, each microcapsule contains positively charged white particles and negatively charged black particles suspended in a clear fluid. When a negative electric field is applied, the white particles move to the top of the microcapsule where they become visible to the user. This makes the surface appear white at that spot. At the same time, an opposite electric field pulls the black particles to the bottom of the microcapsules where they hide. By reversing this process, the black particles appear at the top of the capsule, which now makes the surface appear dark at that spot.

Peruvemba further explained, “To form an E Ink electronic display, the ink is printed onto a sheet of plastic film that is laminated to a layer of circuitry. The circuitry forms a pattern of pixels that a display driver can control. These microcapsules are suspended in a liquid ‘carrier medium’ allowing them to be printed using existing screen printing processes onto virtually any surface, including glass, plastic, fabric and even paper.” He believed that ultimately electronic ink would permit almost any surface to become a display, bringing information out of the confines of traditional devices and into the world around us.

The ink is bi-stable i.e. it requires electrical power only to change its state, making it highly energy-efficient. Although displays based on this ink are not as high-contrast as backlit computer screens, which can make them hard to read in dim light, their reflective surface allows them to be read in daylight situations that could wash out conventional laptop displays.

Lower power consumption

Electronic paper offers all characteristics of paper such as being thin, flexible, and lightweight. It also boasts low power consumption in that it does not require electricity except during screen image changes, making electronic paper especially suited for advertisements or information bulletins in public places for which paper is currently used. Electronic paper is especially convenient for use on curved surfaces, such as columns. In addition, electronic paper is convenient for use in conjunction with mobile devices as an easy-to-read and portable display device.

Unlike other display technologies, once you bring up an image on the display, you can literally unplug the power cord and the image will remain for a year. It is an image-stable display technology. In applications such as electronic newspapers, the reader might take several minutes to read each page and during that entire period, the display does not need power to retain the image.

“Power is once again required when you turn a page. You can now put down your e-book or e-newspaper and come back after an hour, both your power level in the battery and the page on your newspaper will remain where you left it an hour ago. Imagine doing that with your laptop, the battery could be dead by the time you got back unless you went into sleep mode and you have to ‘wake’ the computer which may take a while and may not get you back to where you left off,” added Peruvemba.

Future of EPDs

Beyond today’s generation of technology, which offers the visual look of paper (in terms of contrast, brightness and viewing angle), future versions will integrate E Ink’s flex-ready products with plastic electronics being developed by several companies including a Philips spin-off called Polymer Vision, Epson, LG Display, Samsung and UK-based Plastic Logic. The integration of these two technologies will allow something that not only has the look of paper, but also is also much closer to its form—thin, light, flexible, and rollable.

Peruvemba commented, “The vision of E Ink is to combine these attributes to create RadioPaper, a lightweight, flexible display with the readability of ink on paper but with the added benefit of digital technology to download newspaper headlines or a best-selling novel at the user’s command—providing information to anyone, anywhere. In the future, clothing, buildings, household objects and information appliances all will have the ability to communicate.”

e-Paper has the potential to stop the wholesale destruction of forests to produce paper, and perhaps more significantly, in commercial terms will make reading material much cheaper for the consumer. Users would only need to buy one plastic e-newspaper manifold, for example, and maybe another one to download your magazines. With mass production, these items will become much cheaper than hacking down trees.

“Although many potential applications for e-paper technology exist, one of the more exciting products is the e-paper reader, which in the future might replace the age-old newspaper and possibly even certain types of books. Some technical literature might be perfectly suited for e-paper,” said Khorana.

Experts believe that e-Paper is a decade away in its fully functional format. Nevertheless, this might be a little pessimistic. Early prototypes are available and it does not usually take this long to get a product to market in the IT world. You only have to think back a decade and remember that Bill Gates was saying that the Internet was a passing fashion, while today the Internet is a part of our daily lives.

The launch of ‘Amazon Kindle’—a revolutionary wireless reading device, which was completely sold out within hours of its launch, is just the beginning.

nivedan.prakash@expressindia.com