For some time now, we've been treated to descriptions of the tremendous benefits that flexible displays will bring, but actual display devices have been slow in coming. Recent indications, however, are that flexible displays are beginning to appear in earnest. Opinions differ widely over where their greatest perceived value will lie: in their inherent ruggedness, thinness, light weight, or design freedom, or in some other factor altogether.
At this summer's Society for Information Display conference, two companies demonstrated a new concept enabled by flexibility: the e-skin, a concept in which the display covers all (or most) of the electronic product's front surface. Kent Displays Inc. demonstrated a cell phone with a face that incorporates one big, irregularly shaped pixel. This Ch LCD (cholesteric liquid-crystal display) pixel provides a medium for the user to change the color of the cell phone to any of nine distinct colors. E Ink Corp., in turn, showed a Hitachi Mobile cell phone with a dot-matrix EPD (electrophoretic display) e-skin. The face of the phone displays a set of 95 stored graphics and patterns.
Elsewhere, flexible displays are having their ups and downs. On the up side, Esquire magazine revealed this July that its 75th anniversary cover will be an electronic cover based on a flexible E Ink EPD. On the down side, Polymer Vision recently noted that its much heralded Readius e-reader has been delayed again, this time until the second half of 2008. Moreover, the first Readius incarnation, originally crafted with a 5-inch roll-out E Ink display, will have a foldout display, instead. The reason, according to the company, is user discomfort with roll-out reliability, although the displays readily withstand 15,000 withdraw/insertion cycles. The displays are active matrix (AM) devices using organic thin-film transistors.
Prime View International was the first to market flexible AM EPDs, first demonstrated in 2007. These are based on a circuitry transfer technology licensed from Philips that allows an AM to be fabricated on rigid glass and then transferred to a flexible substrate. First products include 1.9-, 6- and 9.7-inch devices based on E Ink technology.
The first flexible active-matrix electrophoretic displays use circuitry fabbed on glass and transfered to plastic. |
Bridgestone Corp., best known as a tire manufacturer, demonstrated flexible e-paper displays at SID 2008 based on its home-grown ELP (Electronic Liquid Powder) material and QR-LPDs (Quick Response Liquid Powder Displays). The demos of this EPD variant included a curved 10-inch QR-LPD on a flexible glass substrate.
When it comes to near-term plans, however, Bridgestone will be using polyester-film when it starts producing flexible QR-LPDs at the end of 2008. The primary appeal of flexibility, said Bridgestone manager Takahiro Matsuse, is "safety" (greater resistance to damage and breakage than rigid displays).