Tag Archives: foldable displays

World’s first full-color, flexible thin-film reflective display: a step forward for camouflage?

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Caption: Dr. Chanda used an iconic National Geographic photographic of an Afghan girl to demonstrate the color-changing abilities of the nanostructured reflective display developed by his team. Credit: University of Central Florida, used with permission from National Geographic

Caption: Dr. Chanda used an iconic National Geographic photographic of an Afghan girl to demonstrate the color-changing abilities of the nanostructured reflective display developed by his team. Credit: University of Central Florida, used with permission from National Geographic

This has gotten a lot of attention. A June 25, 2015 news item on Azonano describes a couple of possible applications,

Imagine a soldier who can change the color and pattern of his camouflage uniform from woodland green to desert tan at will. Or an office worker who could do the same with his necktie. Is someone at the wedding reception wearing the same dress as you? No problem – switch yours to a different color in the blink of an eye.

A June 24, 2015 University of Central Florida news release on EurekAlert, which originated the news item, provides some insight into the research along with some technical details,

Chanda’s [Professor Debashis Chanda] research was inspired by nature. Traditional displays like those on a mobile phone require a light source, filters and a glass plates. But animals like chameleons, octopuses and squids are born with thin, flexible, color-changing displays that don’t need a light source – their skin.

“All manmade displays – LCD, LED, CRT – are rigid, brittle and bulky. But you look at an octopus, they can create color on the skin itself covering a complex body contour, and it’s stretchable and flexible,” Chanda said. “That was the motivation: Can we take some inspiration from biology and create a skin-like display?”

As detailed in the cover article of the June issue of the journal Nature Communications, Chanda is able to change the color on an ultrathin nanostructured surface by applying voltage. The new method doesn’t need its own light source. Rather, it reflects the ambient light around it.

A thin liquid crystal layer is sandwiched over a metallic nanostructure shaped like a microscopic egg carton that absorbs some light wavelengths and reflects others. The colors reflected can be controlled by the voltage applied to the liquid crystal layer. The interaction between liquid crystal molecules and plasmon waves on the nanostructured metallic surface played the key role in generating the polarization-independent, full-color tunable display.

His method is groundbreaking. It’s a leap ahead of previous research that could produce only a limited color palette. And the display is only about few microns thick, compared to a 100-micron-thick human hair. Such an ultrathin display can be applied to flexible materials like plastics and synthetic fabrics.

The research has major implications for existing electronics like televisions, computers and mobile devices that have displays considered thin by today’s standards but monstrously bulky in comparison. But the potentially bigger impact could be whole new categories of displays that have never been thought of.

“Your camouflage, your clothing, your fashion items – all of that could change,” Chanda said. “Why would I need 50 shirts in my closet if I could change the color and pattern?”

Researchers used a simple and inexpensive nano-imprinting technique that can produce the reflective nanostructured surface over a large area.

“This is a cheap way of making displays on a flexible substrate with full-color generation,” Chanda said. “That’s a unique combination.”

Here’s a link to and a citation for the paper,

Polarization-independent actively tunable colour generation on imprinted plasmonic surfaces by Daniel Franklin, Yuan Chen, Abraham Vazquez-Guardado, Sushrut Modak, Javaneh Boroumand, Daming Xu, Shin-Tson Wu & Debashis Chanda. Nature Communications 6, Article number: 7337 doi:10.1038/ncomms8337 Published 11 June 2015

This paper is open access.

The age of the ‘nano-pixel’

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As mentioned here before, ‘The Diamond Age: Or, A Young Lady’s Illustrated Primer’, a 1985 novel by Neal Stephenson featured in its opening chapter a flexible, bendable, rollable, newspaper screen. It’s one of those devices promised by ‘nano evangelists’ that never quite seems to come into existence. However, ‘hope springs eternally’ as they say and a team from the University of Oxford claims to be bringing us one step closer.

From a July 10, 2014 University of Oxford press release (also on EurekAlert but dated July 9, 2014 and on Azoanano as a July 10, 2014 news item),

A new discovery will make it possible to create pixels just a few hundred nanometres across that could pave the way for extremely high-resolution and low-energy thin, flexible displays for applications such as ‘smart’ glasses, synthetic retinas, and foldable screens.

A team led by Oxford University scientists explored the link between the electrical and optical properties of phase change materials (materials that can change from an amorphous to a crystalline state). They found that by sandwiching a seven nanometre thick layer of a phase change material (GST) between two layers of a transparent electrode they could use a tiny current to ‘draw’ images within the sandwich ‘stack’.

Here’s a series of images the researchers have created using this technology,

Still images drawn with the technology: at around 70 micrometres across each image is smaller than the width of a human hair. Courtesy University of Oxford

Still images drawn with the technology: at around 70 micrometres across each image is smaller than the width of a human hair. Courtesy University of Oxford

The press release offers a technical description,

Initially still images were created using an atomic force microscope but the team went on to demonstrate that such tiny ‘stacks’ can be turned into prototype pixel-like devices. These ‘nano-pixels’ – just 300 by 300 nanometres in size – can be electrically switched ‘on and off’ at will, creating the coloured dots that would form the building blocks of an extremely high-resolution display technology.

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‘We didn’t set out to invent a new kind of display,’ said Professor Harish Bhaskaran of Oxford University’s Department of Materials, who led the research. ‘We were exploring the relationship between the electrical and optical properties of phase change materials and then had the idea of creating this GST ‘sandwich’ made up of layers just a few nanometres thick. We found that not only were we able to create images in the stack but, to our surprise, thinner layers of GST actually gave us better contrast. We also discovered that altering the size of the bottom electrode layer enabled us to change the colour of the image.’

The layers of the GST sandwich are created using a sputtering technique where a target is bombarded with high energy particles so that atoms from the target are deposited onto another material as a thin film.

‘Because the layers that make up our devices can be deposited as thin films they can be incorporated into very thin flexible materials – we have already demonstrated that the technique works on flexible Mylar sheets around 200 nanometres thick,’ said Professor Bhaskaran. ‘This makes them potentially useful for ‘smart’ glasses, foldable screens, windshield displays, and even synthetic retinas that mimic the abilities of photoreceptor cells in the human eye.’

Peiman Hosseini of Oxford University’s Department of Materials, first author of the paper, said: ‘Our models are so good at predicting the experiment that we can tune our prototype ‘pixels’ to create any colour we want – including the primary colours needed for a display. One of the advantages of our design is that, unlike most conventional LCD screens, there would be no need to constantly refresh all pixels, you would only have to refresh those pixels that actually change (static pixels remain as they were). This means that any display based on this technology would have extremely low energy consumption.’

The research suggests that flexible paper-thin displays based on the technology could have the capacity to switch between a power-saving ‘colour e-reader mode’, and a backlit display capable of showing video. Such displays could be created using cheap materials and, because they would be solid-state, promise to be reliable and easy to manufacture. The tiny ‘nano-pixels’ make it ideal for applications, such as smart glasses, where an image would be projected at a larger size as, even enlarged, they would offer very high-resolution.

Professor David Wright of the Department of Engineering at the University of Exeter, co-author of the paper, said: ‘Along with many other researchers around the world we have been looking into the use of these GST materials for memory applications for many years, but no one before thought of combining their electrical and optical functionality to provide entirely new kinds of non-volatile, high-resolution, electronic colour displays – so our work is a real breakthrough.’

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The phase change material used was the alloy Ge2Sb2Te5 (Germanium-Antimony-Tellurium or GST) sandwiched between electrode layers made of indium tin oxide (ITO).

I gather the researchers are looking for investors (from the press release),

Whilst the work is still in its early stages, realising its potential, the Oxford team has filed a patent on the discovery with the help of Isis Innovation, Oxford University’s technology commercialisation company. Isis is now discussing the displays with companies who are interested in assessing the technology, and with investors.

Here’s a link to and a citation for the paper,

An optoelectronic framework enabled by low-dimensional phase-change films by Peiman Hosseini, C. David Wright, & Harish Bhaskaran. Nature 511, 206–211 (10 July 2014) doi:10.1038/nature13487 Published online 09 July 2014

This paper is behind a paywall.

E-readers: musings on publishing and the word (part 1 of 3)

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There’ve been a lot of online articles about e-readers in the last few weeks in particular as debate rages as to whether or not this technology will be viable. It got me to thinking about e-literature, e-readers, e-books, e-paper, e-ink, e-publishing, literacy and on and on. I’ve divided my musings (or attempts to distinguish some sort of pattern within all these contradictory developments) into three parts.This first part is more concerned with the technology/business end of things.

Samsung just announced that it was moving out of the e-reader business. From an article (Aug. 25 2010) by Kit Eaton in Fast Company,

Need any evidence that the dedicated e-reader is destined to become a mere niche-appeal device? Here you go: Tech giant Samsung is ditching its clever e-paper business after years of clever successes and a ton of research into what may be the future for the technology.

Back in 2009 at CES Samsung teased its good-looking Kindle-challenging e-reader, the Papyrus, which used Samsung’s own proprietary electronic ink system for the display. At CES this year it followed up with its “E6” device, with a rumored cost of $400. Samsung had been shaking the e-paper world since late in 2008 with numerous e-paper announcements, including revealing a color 14-inch flexible e-paper display as long ago as October 2008, which used carbon nanotube tech to achieve its sharp image quality.

Now it seems that revolutions in the e-reader market (namely that odd race-to-the-bottom in pricing over quality of service) combined with revolutions in the tablet PC market (which means the iPad, which can do a million more things than the Papyrus or E6 could) and pricing that neatly undercuts Samsung’s planned price points has resulted in Samsung killing its e-paper research and development.

According to Eaton, Samsung hasn’t entirely withdrawn from the e-reader business; the company will be concentrating on its LCD-based systems instead. Samsung is also releasing its own tablet, Galaxy Tab as competition to Apple’s iPad,  in mid-September 2010 (Sept. 2, 2010 news item at Financial Post website).

Dan Nosowitz also writing for Fast Company presents an opinion (Aug. 12, 2010 posting) which sheds light on why Samsung is focusing on LCD -based readers over e-ink-based readers such as Kindle and Nook,

E-ink is one of the more unusual technologies to spring up in recent years. It’s both more expensive and less versatile than LCD, a long-established product seen in everything from iPods to TVs. It’s incredibly specific, but also incredibly good at its one job: reading text.

E-ink e-book readers like the Amazon Kindle and Barnes & Noble Nook offer, in the opinion of myself and many others, the best digital book-reading experience available. …

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E-ink will die mostly because it fundamentally can’t compete with tablets. That’s why announcements like today’s, in which E-Ink (it’s a company as well as that company’s main–or only?–product) claimed it will release both a color and a touchscreen version by early 2011, is so confusing. But color and interface are hardly the only obstacles e-ink has to overcome to compete with tablets: Its refresh rates make video largely impossible, it can’t cram in enough pixels to make still photos look any more crisp than a day-old McDonald’s french fry, and, most damnably, it’s still extremely expensive.

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Amazon showed that the way to make e-book readers sell like blazes is to lower the price to near-impulse-item territory. Its new $140 Kindle sold out of pre-orders almost immediately, and there’s been more buzz around the next version than can be explained through hardware upgrades alone. It’s a great reader, don’t get me wrong, but its incredible sales numbers are due in large part to the price cut.

That comment about the price cut for the e-reader as being key to its current success can certainly be borne out by this article E-reader faceoff: Kindle or Nook? Here’s a comparison by Mark W. Smith on physorg.com

There’s a titanic battle brewing in the e-reader market. The Amazon Kindle and Barnes & Noble Nook are leaving competitors in the dust this summer and are locked in a war that has dropped prices by more than half in just a year.

and with this article E-readers gain steam with lower prices and new models by Christine Matthias on Salon.com,

The Wall Street Journal and Tech News Daily have a few things you should consider before wading into the increasingly crowded e-book market, as well as new research that reveals folks with an e-reader tend to read a whole lot more than ever before. The Barnes and Noble Nook is trying to wrestle some market share away from the big boys, and Sharper Image just announced a new e-reader called the Literati that hopes to, maybe, nail down more male readers? It’s got a color screen, in any event.

Or you could get a library card. It’s free.

Addy Dugdale at the Fast Company site in her article, Borders Cuts E-Reader Prices as Kindle Goes to Staples, has this to say,

Borders has slashed the prices of E-Readers Kobo and Aluratek by $20, illustrating just how meh they’ve become in the tech world. The price drop is nothing new–both the Kindle and Nook, Amazon and Barnes & Noble’s market leaders, have seen their prices slashed recently, and they’re thought to be the most exciting brands in the sector. But who does the news bode worst for?

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But most of all, this news proves that, as my colleague Kit Eaton pointed out a few months back, this is about as good as it gets for the e-Reader. It’s not quite dead, but it’s looking a bit peaky, like. The reason is, of course, the tablet.

There are efforts that may revive e-readers/e-books/e-paper such as this, a new development in the e-paper/e-reader market was announced in a news item on Azonano (Aug.27, 2010),

The FlexTech Alliance, focused on developing the electronic display and the flexible, printed electronics industry supply chain, today announced a contract award to Nyx Illuminated Clothing Company to develop a foldable display constructed from a panel of multiple e-paper screens.

Applications for this type of product are numerous. For consumer electronics, a foldable display can increase the size of e-reader screens without increasing the device foot-print. In military applications, maps may be read and stored more easily in the field. Medical devices can be enhanced with more accessible and convenient patient charts.

“To enable this unique technology to work, our engineers will develop circuitry to simultaneously drive six separate e-paper screens as one single display,” described John Bell, project manager for Nyx. “The screen panels will be able to be folded up into the area of a single panel or unfolded to the full six panel area on demand.”

Convenience is always important and a flexible screen that I could fold up and fits easily into a purse or a pocket offers  a big advantage over an e-book or an iPad (or other tablet device). I’d be especially interested if there’s a sizing option, e.g., being able to view in 1-screen, 2-screen, 3-screen and up to 6-screen options.

As for the debate about tablets vs e-readers such as Kindle, Nook, and their brethren, I really don’t know. E-readers apparently offer superior reading experiences but that presupposes interest in reading will be maintained. Something like Mongoliad (as described in my Sept. 7, 2010 posting), for example, would seem ideally suited to a tablet environment where the reader becomes a listener and/or a participant in the story environment.

Tomorrow: Part 2 where I look at the reading and writing experience in this digital world.