Breakthrough e-display means electronics with high speed, high readability and low power usage

Oct 05, 2010
UC student Shu Yang holds prototypes of the e-Display technology developed by UC. Credit: Lisa Ventre, U. of Cincinnati

Today's Oct. 4 issue of the high-impact journal, Applied Physics Letters, contains a new electrofluidics design from the University of Cincinnati and start-up company Gamma Dynamics that promises to dramatically reshape the image capabilities of electronic devices.

This patent-pending electrofluidics breakthrough by the Novel Devices Laboratory at the University of Cincinnati and partner companies Gamma Dynamics, Dupont and Sun Chemical follows about seven years of work. According to lead researcher Jason Heikenfeld, UC associate professor of electrical and computer engineering in the College of Engineering & Applied Science, and John Rudolph, president of Gamma Dynamics, the breakthrough is even more impressive when you realize that similar research efforts elsewhere have lasted a decade without achieving similar results.

Importantly, this new "zero power" e-Design from UC can be manufactured with existing equipment and technology.

Said Heikenfeld, "What we've developed breaks down a significant barrier to bright electronic displays that don't require a heavy battery to power them."

He explained that, currently, fall into two basic camps. The first includes those devices that offer limited function and slow speed but require little power to operate. These would include e-readers like the Kindle.

In the second camp, devices like cell phones, laptops and the iPad provide high color saturation and high-speed capability for video and other functions but at a cost of high power usage.

Heikenfeld stated, "Conventional wisdom says you can't have it all with electronic devices: speed, brightness and low-cost manufacturing. That's going to change with the introduction of this new discovery into the market. This idea has been in the works for a while, but we did not start really pushing the project until we thought we could make it manufacturable."

The two horizontal "boxes" above represent views of the new technology design -- with the pigment dispersion fluid represented as "in motion." Ambient light enters via the device screen. When that light hits the layer of reflective electrodes, it is amplified. Credit: Jason Heikenfeld and Angela Klocke, U. of Cincinnati

Before describing UC's new "zero-power" design, it's helpful to understand the basic design of existing electronic devices.

Think of an e-reader as a bunch of micro-sized buckets (or pixels) of mixed black and white paint, where you can move the black and white pigments to the top or the bottom of the bucket. Just like mixing paint, the process is not fast. That's somewhat close to how today's e-readers work. The slow movement of these particles forms the text and grayscale images you see on an e-reader. These devices use practically no power unless you are switching the screen. It's actually making use of ambient light to make the particles visible. When the user turns the device on or off or switches a page, he's electronically "mixing the paint" (or pixels) to create the overall image or text page.

Faster, color-saturated, high-power devices like a computer's liquid-crystal screen, an iPad or a cell phone require high power, in part, because they need a strong internal light source within the device (that "backlights" the screen) as well as color filters in order to display the particles as color/moving images. The need for an internal light source within the device also means visibility is poor in bright, natural light.

The new "zero-power" design combines the best features of both these kinds of devices. It requires low-power because it makes use of ambient light vs. a strong, internal light source within the device. As such and because of its low-power requirements, this new technology will make for more environmentally friendly electronic devices, stated Heikenfeld.

Yet, even though an electronic device with this eletrofluidic technology would lack a strong, internal light source, it would still display bright images at high speed. How?

Behind the display screen are two layers of liquid (oil and a pigment dispersion fluid like an inkjet fluid). Between the two layers are reflective electrodes. Think of these electrodes as a highly reflective mirror.

Ambient light enters through the display screen and through the first layer of liquid and hits the reflective electrodes. When the light hits that reflective electrode, it bounces back out to the viewer's eye, creating the perception of a bright, color-saturated image…or text or video… .

A small electric charge powers the movement of these oil and pigment-dispersion liquids. The movement occurs between a bottom layer behind the reflective electrodes and a top layer in front of the reflective electrodes. When the pigmented substance is positioned in the "top" layer (sandwiched between the ambient light and reflective electrodes), it creates a reflected ray of colored light which combines with literally millions of ambient light rays to produce a full-color display.

(The closest competition with similar brightness is electrochromic technology, which does not switch quickly enough to create video images. And the closest competition that is really low power but can still "do" video is called "Mirasol" technology developed by Quallcomm. However, when trying to display a color like white, the "Mirasol" technology has about one-third the brightness level of the UC technology being announced today. "Mirasol," in fact, resembles greyed newsprint.)

Importantly, the new e-Display design published today is manufacturable with current facilities and technology.

Manufacturability using the same equipment as that used for current LCDs was essential since a new LCD plant costs around $2 billion.

UC's Jason Heikenfeld, at left, and student Shu Yang demonstrate how the technology developed by UC can employ bright, incident light by reflecting it. Many of today's electronic devices, like the BlackBerry held by Heikenfeld, cannot do so. Credit: Lisa Ventre, U. of Cincinnati

According to Gamma Dynamics' Rudolph, this electrofluidics breakthrough will change the display technology used in a myriad of electronic devices. e-Readers like the Amazon Kindle will be able to display color and video. Devices like cell phones and iPads will require much less power and will be readable even in bright sunlight.

He estimated consumers will likely first see it in action as grocery-store shelf labels and advertising displays in about three years' time.

Currently, liquid-crystal displays are attached to some grocery-store shelves, providing product and price information. These run on battery power; however, the batteries are insufficient to meet the LCDs' high power requirements. So, their brightness levels are insufficient to attract shoppers' attention. Stores still attach paper labels to them in order to indicate sale items or barcodes with eye-catching brightness.

Rudolph said that by substituting the UC-developed electrofluidic e-Display technology, these shelf-label devices would become bright and eye-catching. Given the frequency with which shelf labels are updated, the store labels should then operate for at least five years without the need for battery replacement.

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User comments : 14

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apex01
not rated yet Oct 05, 2010
It looks like some of the Minority Report tech will be a reality sooner than thought.
Joro01
not rated yet Oct 05, 2010
The microfluidic systems, especialy driven by electric field aren't something new, but the idea is good. But how it behaves at the 0 or -10 degrees celsius for example?
nicknick
not rated yet Oct 05, 2010
What is the difference with the electrowetting technology from Liquavista, a spin-off from Philips. They are very close to commercialisation and are able to work in both transparant and reflective (zero power mode)?
GSwift7
5 / 5 (1) Oct 05, 2010
I wonder about the lifespan of the display. These things often use organic dye that breaks down too quickly for consumer products. Would you want a cell phone with a screen that started out bright but soon went dim and eventually could not be read after a year or less? They aren't saying anything about it, but the stated applications imply that they aren't ready for consumer electronics.

@nicknick:

The company web site says that this is a variant of electrowetting, so it's a related technology.
GSwift7
not rated yet Oct 05, 2010
ooops, sorry for double.
Kedas
not rated yet Oct 05, 2010
3 years?
Well, I could have told you that without this news article.
xamien
not rated yet Oct 05, 2010
looks my nook is already obsolete. but then, so is every other e-reader. XD
ecotek2u
5 / 5 (1) Oct 05, 2010
Love it! So good to see breakthroughs like this that make the world a better place! Better grocery-store shelf labels and advertising displays. Can't wait. But thats where the money is. Madness?
nanotech_republika_pl
not rated yet Oct 05, 2010
Can somebody point to a better explanation of how the device works? Why oil and the paint in two separate layers? etc.
Riff
5 / 5 (1) Oct 06, 2010
I agree with GSwift7. I had a Phillips MP3 player with OLED display. While the device stayed fully functional, the display slowly faded out (about a year). Now you cant even see the display in pitch black darkness.
Quantum_Conundrum
3 / 5 (2) Oct 06, 2010
Love it! So good to see breakthroughs like this that make the world a better place! Better grocery-store shelf labels and advertising displays. Can't wait. But thats where the money is. Madness?


I think they miss the point. With the exception of parents caving and buying what a child wants, people tend not to buy something from a grocery store except what they already knew they wanted/needed before they even got there.
tkjtkj
not rated yet Oct 06, 2010
I agree with GSwift7. I had a Phillips MP3 player with OLED display. While the device stayed fully functional, the display slowly faded out (about a year). Now you cant even see the display in pitch black darkness.


OLED, as in 'Nexus One'?? how do new OLED's differ from that one in your experience??

tkjtkj@gmail.com
GSwift7
not rated yet Oct 07, 2010
@ nanotech_republika_pl:

Here's a link to a fair explaination of electrowetting on wiki:

http://en.wikiped...owetting

You can also follow the link to microfluidics near the bottom of the page if you want to know more. I would hardly call either of those two pages comprehensive, but they are a good place to start if you are just curious. The two layers basically work like a small magnet. One color will have opposite polarity to the other, so changing the magnetic field in a color cell will flip-flop the two colors up and down, so that one or the other is visible from the viewing side. So in the + mode the pixel may look blue and in the - mode it may look black.
TDK
not rated yet Oct 07, 2010
This principle is called Young-Laplace transposition

http://www.uc.edu...id=10068]http://www.uc.edu...id=10068[/url]

http://www.uc.edu...id=10068]http://www.uc.edu...id=10068[/url]

Well - and no breakthrough occurred. People could be feeded with such reports again and again, because they're forgetting stuffs with few months half-time.