In a news release today, Philips said they are getting closer to being able to produce “rollable displays.” The displays combine active-matrix polymer driving electronics with a reflective “electronic ink” front plane on an extremely thin sheet of plastic. Philips publishes the current status of its technology in the February 1 issue of the scientific magazine Nature Materials.
From the Philips press release:
Lightweight, large-area displays that are unbreakable and can be rolled up into a small-sized housing when not actively used, are particularly attractive for mobile applications. Ultimately, large-area displays could become feasible, which are so flexible that they can be integrated into everyday objects like a pen. The availability of such displays would greatly stimulate the advance of electronic books, newspapers and magazines, and also new services offered by (third generation) mobile network operators. These applications currently depend on fragile, heavy and bulky laptops orsmall, low-resolution displays of mobile phones, which both have clear drawbacks.
Philips not only wants to prove the feasibility of such displays, but also has the ambition to rapidly move towards the development of an industrially feasible process for volume production. Within the Philips Technology Incubator an internal venture has been formed with this aim. The venture is called Polymer Vision ( http://www.polymervision.com).
Polymer Vision builds on years of groundbreaking research in the field of organic electronics within Philips Research, which earlier led to world-first demonstrations of organics-based, functional RFID circuits and active-matrix displays. One key competence of Polymer Vision is the robust fabrication of large arrays of polymer based thin-film transistors (TFTs) with largely identical electrical characteristics. This is combined with the capability to model and design circuitry that exploits the characteristics of organic electronics to the fullest.
Using these strengths, Polymer Vision has been able to make organics-based QVGA (320×240 pixels) active matrix displays with a diagonal of 5 inch, a resolution of 85 dpi and a bending radius of 2 cm. The displays combine a 25 micron thick active-matrix back plane, containing the polymer electronics-based pixel driving, with a 200 micron front plane of reflective ‘electronic ink’ developed by E Ink Corporation. Electronic ink-based displays are thin and flexible by construction because they do not require cell gap control. Moreover, displays made with electronic ink technology are ideal candidates for reading-intensive applications because of their excellent, paper-like readability and extremely low power consumption.
The resulting display represents the thinnest, and most flexible, active-matrix display reported to date. Moreover with close to 80,000 TFTs it is the largest organic electronics-based display yet, with the smallest pixel pitch reported to date. A picture of the display is included below.
Along with the displays, well-functioning shift registers, an important building block of display drivers, are published in the February 1 issue of Nature Materials. These shift registers are the largest functional circuits based on organic electronics reported to date. And, more importantly, they can be fabricated using the same process as used for the back plane TFTs, representing an important step towards the option to realize the complete display drivers on the same substrate as the display. This leads to more robust and reliable displays with smaller footprints and less external connections.
Polymer Vision manufactures active-matrix back planes and shift registers using standard production equipment used in the established AMLCD industry. This allows the use of a mature knowledge base to quickly move up the learning curve towards a fully industrialized process. Currently Polymer Vision has the capability of producing over 5,000 fully functional rollable display samples per year, and it is in the process of defining a pilot production line.
Visit Philips’ Website for more information and images of the technology in use.