Thirty-five years in the making, electronic paper is now closer than ever to changing the way we read, write, study and work — a revolution so profound that some see it as second only to the invention of the printing press in the 15th century. Made of flexible material, requiring ultralow power consumption, cheap to manufacture and easy and convenient to read, e-papers of the future are just around the corner. The promising technology has the potential to hold libraries on a chip and replace most printed newspapers before the end of the next decade..
How E-paper Works
E-paper comprises two parts: The first is electronic ink, sometimes referred to as the frontplane, and the second is the electronics required to generate the pattern of text and images on the e-ink page, called the backplane.
Over the years, a number of methods for creating e-ink have been developed. The Gyricon e-ink developed in the 1970s by Nick Sheridon at Xerox was based on a thin sheet of flexible plastic containing a layer of tiny plastic beads, each encapsulated in a little pocket of oil and able to freely rotate within the plastic sheet.
Each hemisphere of a bead has a different color and a different electrical charge. When an electric field is applied by the backplane, the beads rotate, creating a two-colored pattern. This method of creating e-ink was dubbed bichromal frontplane. Originally, bichromal frontplane had a number of limitations, including relatively low brightness and resolution, and a lack of color. Although these issues are still being tackled, other forms of e-ink, with improved properties compared with the original Gyricon, have been developed since the early days.
One such technology is electrophoretic frontplane, developed by the E Ink Corporation. Electrophoretic frontplane consists of millions of tiny microcapsules, each about as wide as a human hair. Each microcapsule is filled with a clear fluid containing positively charged white particles and negatively charged black particles.
When a negative electric field is applied, the white particles move to the top of the microcapsule, causing the area to appear to the viewer as a white dot, while the black particles move to the bottom of the capsule and are hidden from view. When a positive electric field is applied, the black particles migrate to the top and the white particles move to the bottom, generating black text or a picture.
A drawback of electrophoretic e-ink is its low refresh rate, making electrophoretic e-ink unsuitable for displaying animation or video. Because it takes time for the particles to move from one side of the microcapsule to the other, drawing new text or images is too slow and creates a flicker effect.
A completely different solution for creating e-paper, known as cholesteric liquid crystal display (ChLCD), is being developed by such companies as IBM and Philips, as well as Hewlett-Packard and Fujitsu, which have demonstrated actual devices. ChLCD technology is based on the well-known and widespread technology of liquid crystal displays, which work by applying a current to spiral-shaped liquid crystal molecules that can change from a vertical to a horizontal position.
Although other potential technologies for developing advanced color electronic paper exist, such as photonic crystals (P-Ink), many analysts believe that ChLCD technology could become the dominant e-paper technology of the next decade. The LCD industry has a high level of maturity, and ChLCD technology currently offers what many analysts see as the ideal list of features for e-paper: physical flexibility; thinness, at approximately 0.8 millimeters; light weight; a bistable nature, requiring no power to maintain an image and very little power to change it; good brightness, contrast and resolution; and vivid color and a decent refresh rate capable of displaying animation and possibly even video.
Applications of E-paper
Great progress has been made in the field of e-paper since the invention of Gyricon. At this stage, some of the products based on E ’Ink’s technology are little more than expensive gimmicks, such as ’Seiko’s limited-edition e-paper watch (priced at more than $2,000).
Other products that will be marketed have more substantial applications. E-paper thin color displays for packaging, currently under advanced development at Siemens, could display prices on products dynamically, instantly altering a product’s price when necessary (using such low-power wireless technology as radio-frequency identification, for example). A dynamic expiration date, which would graphically display the amount of time remaining for food and drug consumption, is another potential application.
The potential number of uses of e-paper technology is staggering. In addition to being a new method for labeling foods and drugs, it could be used to label anything from shelves to office binders. One of the original uses of the Gyricon e-ink was in advertising and billboards; the bistable nature of the technology made Gyricon a useful and cost-effective billboard technology. E-paper displays can also be used as low-power digital screens for a variety of electronic appliances, from microwaves to MP3 players.
Although many potential applications for e-paper technology exist, one of the more exciting products is the e-paper reader, which might soon replace the age-old newspaper and possibly even certain types of books; some technical literature might be perfectly suited for e-paper, for example.
Existing readers from Sony, iRex and a number of other companies are still quite expensive and suffer from some of the problems that plagued early technology models. The next generation of e-paper readers, however, will add color, include improved hardware that can refresh pages more quickly, and have more advanced wireless capabilities, making them more versatile devices. They will spur applications such digital maps appealing, especially when connected to GPS hardware and software.
It is possible that the most important applications of this technology have not yet been invented. In the same way that Theodore H. Maiman did not foresee the DVD player when he invented the laser in 1960, we still might be in the dark as to the true potential of e-paper technologies.
The Future of E-Paper
According to Nick Hampshire, an analyst at AFAICS Research, which focuses on publishing and media-related technology, the main obstacle to mass adoption of electronic-paper-based readers is price. According to his research, the cost of an e-paper-based reader has to fall to less than $100 before a significant percentage of the population will buy one. Even then, they will buy only if suitable content is available at a reasonable cost. The second obstacle is then the availability of content.
Hampshire says that giveaway e-paper display products could be a possibility by 2015, and that content availability is a question of making sure publishers are aware of the potential offered by e-paper displays and prepared to make the investment to provide that content. However, the real e-paper revolution, according to Hampshire, will begin as soon as cheap color e-paper displays reach the market, in about three to five years.
Iddo Genuth is the editor of the electronic magazine The Future of Things at www.thefutureofthings.com.