Philips reveals roll-up display

03 Feb 2004

Dutch consumer electronics firm makes a 5-inch flexible organic display.

Philips says that it has manufactured the thinnest, most flexible active-matrix display demonstrated to date. The prototype 5-inch organic display has a resolution of 320x240 pixels (QVGA) and a bending radius of about 2 cm. It combines polymer electronics pioneered by Philips with electronic ink technology developed in the US by the E-ink Corporation.

Roll-up display

Philips says that it has formed an internal venture called Polymer Vision to commercialize the technology and is now in the process of defining a pilot production line. Once they become commercially available, such displays could transform the appearance of mobile phones or PDAs and increase the appeal of electronic books.

The current prototype consists of a 25 micron thick active-matrix backplane that contains the polymer thin-film transistors (TFTs) and row-shift registers that are required to drive the display. The backplane is made by spin-coating a soluble organic semiconductor called pentacene onto a polyimide substrate and then processing it by photolithography. It is estimated to contain around 80,000 TFTs and the largest functional circuits ever built by organic electronics.

A 200 micron thick front-plane based on E ink, electronically-activated pigment, is then laminated on top to complete the display. Philips says that the entire fabrication process, including all the organic electronics takes less than 2 hours.

Display in action

Although the current Philips’ prototypes are small and monochrome the firm is confident that it can improve the performance. “The size can be scaled up in principle. The fact that the polymer electronics can be processed from a solution is an advantage in scaling up because it does not require expensive vacuum equipment,” said a spokesman from Philips. “Grey scales are possible but they require a somewhat more complex driving scheme.”

Perhaps the biggest question mark is whether the display will ever be compatible with video-rate images, at the moment it takes 1 second to load an image. More information on the display and the organic electronics can be found in the latest issue of Nature Materials (Feb 1 2004).

Author
Oliver Graydon is editor of Optics.org and Opto & Laser Europe magazine.