I’m curious about flexible touch screens – why are there not more in the market and what are the challenges and limitations associated with them? What design considerations do I need to be aware of when integrating them?

Dear Mike:

Ancient history, my man.  Curved and flexible, I guess is the new “flat” which is what everybody has wanted in touch screens for that last ten years. If bell bottom pants can come back (they are called “flairs” now), then why not curved touch screens?  In the days of CRTs, all touch screens were formed to match the radius of the CRT tube, primarily to reduce parallax (a fancy word for your finger missing the touch target). This meant that touch screen manufacturers had the tools to precisely bend glass and plastic into most CRT sizes and radii.  We did this without damaging the integrity of the transparent ITO thin film.

Because we’ve switched to LCDs, which are flat, touch panels are now flat too. But if you need your touch panel to be bent then listen for the groans of touch screen manufacturers thinking about which storage shed is housing the forming equipment, or imagine the screams of the LCD manufacturers thinking about bending LCD mother glass. But crazy designers seem to want it
(for example, car-navigation systems are the last flat surface in most vehicles, and they are out to eliminate them), so I guess we will be forming and bending again… Shifts in the microdisplay market, especially those using projectors, might also drive the demand for curved projected capacitive touch panels, as would a flexible OLED display (yeah, yeah, we will all believe in OLED when we see it).

Touch International is getting requests for both formed (holding a shape) and flexible.  Both are possible with projected capacitive technology, which is even more forgiving than the legacy resistive or surface capacitive parts because projected capacitive starts as a digital sensor instead of an analog sensor, meaning changes in resistance (from the flexing) are not as important.

Although most projected capacitive touch panels are glass— for reasons of cost, scratch resistance, stability and optical clarity— it is only a matter of time before they are all plastic. To make a formed glass panel, because the volume is practically non-existent, it is more expensive than difficult, but you should be prepared for volume to get interest from any of us.  Formed or
flexible touch panels made from plastics, are possible in lower volumes.  And with the advent of better hardcoats, approaching the scratch resistance of glass, we are ready to start up our old furnaces again…that is, if we can find them.

To your second question, there are no special design considerations that are different from the contemporary glass panels. The most important concern is the available border area (non-visible area). The smaller (tighter) you make it, the higher the price….a tiny border can double the price over a larger boarder.  Touch Guy also wants to emphasize that software is just as important…we can make you a roll-up keyboard, but you will need to deal with the ergonomics of multiple fingers resting on the keyboards. And last, while bending and forming touch screens is old technology, it is new to all but the legacy touch companies, so some patience may be necessary.

Until next time,

Touch Guy