Electronic paper, or ePaper, is not a term for a substance, but for a display device. Not to be confused with digital paper (which is used with a digital pen to make digital documents that are handwritten), e-paper aims to reproduce as closely as possible the experience of reading printed documents on paper. The most well-known devices are probably Amazon’s Kindle e-readers, but e-paper is also used in room signs for space management and digital signage.
A Short History of E-paper
Devices like e-readers use e-paper, which in turn uses e-ink. That’s a lot of “e-”s. but the “e” simply stands for “electronic” and has become a fairly standard way of naming things since the creation of email in the 1960s (though it was called electronic mail until around 1993, when “electronic” got shortened to ”e” plus a hyphen, and then eventually the hyphen itself went away).
Way back in the 1970s, Nick Shendon invented Gyricon for Xerox in Palo Alto – a tiny rotating ball (around 100 micrometres) containing a janus particle (named after the two-faced Roman god of beginnings and endings, who gave us the name of the month of January). This is a nanoparticle that can have two or more separate physical surface properties. These particles have negatively charged black plastic on one side, and positively charged white plastic on the other. By putting these in a grid inside a transparent silicone sheet and suspending them in a small bubble of oil, they can rotate to either side, depending on if a charge sent to them is negative or positive.
That’s the genesis of e-ink. The idea was to facilitate a paperless office, and to mimic the look of ink on paper as closely as possible. So, when a particle has its black side facing up, it looks like ink and when its white side is facing up, it looks like blank space. Thus, words and pictures can be easily formed, and the brain processes the information in the same way it processes printed books and newspapers.
In 1997, Barrett Comiskey, Joseph Jacobson and JD Albert at MIT’s Media Lab built on this work, creating the first real electronic paper displays. Instead of a rotating plastic ball, there was now a round chamber filled with clear fluid that contained various black and white particles which float up to the top of the sphere and stick, depending on the electric charge they receive. That same year, they co-founded the E Ink Corporation, which continued to improve the product. In 2001, they introduced the active matrix electronic paper display, which allowed the addition of color changes
Then, in 2004, researchers at Philips created inexpensive, thin flexible sheets of electronic paper, greatly reducing costs. Sony used this technology to create the first e-reader, the Sony Librie. This reader, while a bit slow and not super high-resolution, could display texts that could be read in direct sunlight and needed no power at all to maintain an image – it only used power when changing the image, or page.
Three years later, Amazon launched the Kindle, the success of which drove innovation and brought costs down even further. In 2010, e-paper entered the digital signage world with smart shelf labels – small displays at cashier desks and near products in a store that displayed up-to-date information about products and pricing. These were easy to install, lightweight, needed no wires, and were easy to read from almost any angle – even in direct light.
2014 saw the first jumbo e-paper display introduced. These 32-inch displays are 25 times larger than standard e-readers, and have been used in museums and retail establishments for advertising, digital signage, wayfinding and more. 2014 also saw the first introduction of room signs using e-paper and e-ink. Visix premiered its own e-paper room sign at InfoComm that same year.
In 2015, Australia began using solar-powered e-paper traffic signs to inform the public, and the City of London installed e-paper displays at bus stops, showing real-time arrival and departure information, interactive route maps and more. That same year, Yusuke Komazaki developed e-paper that could be written on with a magnet.
In 2016, Visionect’s RGBW filter! Advanced Color e-paper displays were debuted at SID Display Week in San Francisco – the first consumer full-color e-paper displays that didn’t use a color-filter array. In Europe, e-paper displays began showing up on long-distance trucks showing targeted advertising, information on traffic jams, distance to the next gas station, and other helpful information for drivers. The Estonian National Museum also began using e-paper displays for interactive screens and digital labels to enhance the visitor experience. And the E Ink Corporation launched their largest display yet, a 42-inch e-paper screen, at CES 2017 in Las Vegas.
That’s where we are today. The resolution is still too low to display moving images, though this hurdle will likely be overcome in the very near future.
Why ePaper Matters
Why all this work on e-paper displays? What are the advantages over LED and LCD screens?
First off, they are a lot cheaper to buy and operate. They use only 1% of the power of an LCD display, and can be used both indoors and outdoors and still be just as easy to read, even in direct sunlight. Just consider the project pioneered in Sydney with street signs – a city like Los Angeles puts over half a million temporary street signs up each year, at a cost of $9.5 million. Having e-paper signs, where you can change what they say by typing in a few things into a software app, would save an enormous amount of time and money.
Because they aren’t backlit, e-paper signs are much easier on the eye. Though research says that e-readers are not inherently better for your eyes than backlit displays (which have a flicker that can cause eyestrain and headaches with prolonged use), the fact is that human eyes are designed to use reflected light rather than projected light. And most LCD or LED screens have a glossy finish, which creates visual noise that our eyes have to work harder to overcome, especially in bright environments.
This technology is taking off and being applied in surprising places. Some retail stores are using e-paper to display prices and sales; buses and trams are using e-paper to display their numbers and routes; there are e-paper luggage tags and even e-ink tattoos. Some industry insiders predict that e-paper will overtake and surpass other types of displays within the next ten years.
Digital Signage and e-Paper
Once e-paper can display moving images at the same speeds and resolutions as LCD and LED displays, many organizations will likely make the switch. The fact that these devices use so little power is simply too attractive.
For now, e-paper and e-ink room signs are being used more and more. They’re lightweight, wireless and powered with batteries, so they can be mounted anywhere you like, and moved around easily as a space or location gets reconfigured. They’re also great for office hoteling, and can integrate with calendaring systems so information is updated automatically. Paper-white signs offer even higher contrast to enhance readability, plus have both black and red ink options.
And the energy usage savings cannot be overstated – these signs use 1% of the power of other displays. Think of it like this – assuming your displays are on for ten hours a day, five day a week, you can power an e-paper sign for two weeks for the same energy cost as powering an LED or LCD screen for one hour. Or, for the same cost as powering a single display for a week, you can power an e-paper display for two years. That’s a lot cheaper, and much more environmentally friendly besides.
As the world goes more and more digital, e-paper is poised to become the technology of choice. One day, we’ll even have tablets and smartphones that use it. But if you’re looking for a room management and scheduling solution right now, e-paper and e-ink room signs are the most affordable, most flexible option available today.