Researchers at Arizona State University’s Flexible Display Center are developing flexible video displays. Learn about the people involved and the manufacturing process.
Researchers at Arizona State University are working on a dream of flat, flexible video displays. Scientists are figuring out how to engineer the screen and design a manufacturing process. Mike Sauceda and Scott Olson tell us more about the flexible display center at A.S.U.
Ever since television was invented people have been envisioning a flat flexible display. We have flat screens at home. The dream of the flat display is made a reality at the Arizona State University Flexible Display Center.
The Flexible Display Center was founded a little over five years ago with a substantial contract from the Army. In its first five years, it represents about $100 million in investment, about evenly split between the U.S. Army and Arizona State University, taxpayers of Arizona. The purpose was to try and accelerate the solution of engineering problems associated with making flexible display an actual reality.
Prototypes have been developed and tested by the Army. The Army liked the work being done by the Flexible Display Center so much it signed up for another five-year, $50 million contract.
They have made significant progress. It's honestly somewhat stunning to me how much progress they have made over the last five years. And I foresee even greater progress in the future, getting more into the domain of color, and reducing the power demands that go into these devices to make them really rugged and portable so we can give them to our soldiers in the field in the future.
The exciting thing from the University's perspective is that this is a new way for doing business because the way that this problem was articulated was very different than I think some many others which is the articulation of what the technological application would be, without all of the science having already been worked out. And not the technology not worked out and the manufacturing not work out. Meaning some of the science actually isn't worked out. Please do all of those things together at the same time rather than in a linear fashion which then elongates the process to solution.
While the Army is still a driving force for the work going on in the Flexible Display Center, the school has many industrial partners some of whom provide the material used for displays. The result has been small flat screens at first made on stainless steel and now plastic.
Steel is heavier. It's electrically conducting which provides some additional headaches from a technical point of view. It has a tendency to crease and dent in ways that are not -- that compromise the mechanical robustness of the display. You also can't see through it which turns out to be important in the architecture of some display technologies. For example, organic displays and all of those things motivated the migration to plastic.
The flexible displays are made using three types of technologies. Two of the technologies use materials that reflect light instead of producing their own. What the advantage being a still image can be up on the screen with no power required. Power is only required to change the image.
We have three core electro-optic materials we are working with in conjunction with our partners. First and primary one is technology called E-ink. That's a company out of Cambridge, Massachusetts, and what exactly as you said there is black and white ball suspended in a microcapsule and by applying a voltage on our back plane you are able to move or right the image much like the appearance of newsprint. And so it's been coined by many in the industry E-paper as part of that work. And it's very low power. Very, very good in direct sunlight. And very rugged. The E-ink itself is also another plastic material that's laminated on top of our plastic back plane. So it's fully plastic when it's fully integrated and built. Second technology we have is from a company Kent Displays in Kent, Ohio, and is a liquid crystal technology and it's a reflective technology like E-ink but here there's a liquid crystal material not very much different from liquid crystal materials in your flat panel TVs at home but instead of letting light through the liquid crystal is bent in such a way it reflects light of certain wavelengths. And so there you apply again a voltage and you either block the light or allow the light to pass through. And you get either a kind of black and white or gray image that's part of that.
While the first two technologies are inherently black and white that can be made into a color screen the third technology is inherently color and requires constant power to maintain an image because it produces its own light.
The third electro-optic technique we are working on here at the center is something called organic light emitting displays. And they are very interesting technology in that they are full color video rate type displays very much like liquid crystal displays that are in your living rooms today. The big difference with OLEDs is instead of using a back light and color filters to let light through OLED displays are pixilated red, green, and blue, organic materials on top of our back plane that then switch just like a conventional TV. What that allows is the organic materials are integrated directly on the TV. You make very thin, very low power flexible full color display.
Materials to turn the plastic disks into displays are deposited on to the substrate through vacuum vapor deposition where thin layers of metal are built up. The flexible display center has a full manufacturing line to work out the challenges of putting the display on a flexible material as opposed to a rigid surface.
We work in two substrates. This is from our partner DuPont Films. And there's a lot of aspect to that. The first we had to lower the manufacturing temperature to be compatible with this flat plastic. It melts at 210 degrees Centigrade. We had to spend about a year working on these new lower temperature semi-conductor manufacturing processes to make sure that nothing came out warped, bowed, melted or burned as part of the process. The second challenge we had to do is that glass is atomically smooth. It's atomically smooth. Plastic, while it looks smooth, scratches very easily, and so we worked very closely with our partner to develop a coating on top of this plastic that makes it as smooth as glass, even through some handling. Like a hard coat property to allow regular handling before you actually get into it the manufacturing process to avoid all of that, excuse knee, any of that defectivity.
Although the traditional manufacturing method is being used to make Flexible Display the dream is to make everything flexible and have a device totally flat and flexible.
That includes sensor, imaging arrays, a variety of platforms that can be integrated into fully electronic flexible systems so you can have your flexible memory, your flexible power, and your flexible display all on one substrate.
Shawn O'Rourke:Director, ASU Flexible Display Center