Curved touchscreens

CES 2014 was the modern technology equivalent of the voyage of Ferdinand Magellan, proving beyond any shadow of doubt displays no longer can be thought of as only flat. While the massive curved 105-inch TVs shown by LG and Samsung drew many gawkers, the implications of curved touch displays are even wider.

At DAC 50 there were more than a few chuckles and some mystified looks when Samsung’s Dr. Stephen Woo spent a lot of his keynote address highlighting flexible displays as one of the challenges for smarter mobile devices (spin to the 27:41 mark of the video for his forward-looking comments). I think if we had polled that room at that second, there would have been two reactions: 1) yeah, right, a flexible phone, or 2) hmmmm, there must be something else going on. His comments should have provided the clue the flat display theory was about to dissolve:

Is there any major revolution coming to us? My answer to that is yes. I’m afraid that we as EDA, as well as the semiconductor industry, are not fully appreciating the magnitude of the revolution.

Woo showed the brief clip from CES 2013 introducing the first Samsung flexible display prototype, hinting that while exciting, it is still a ways from practicality. Why? He went on to explore the rigid structure of the current high volume smartphone – flat display, flat and hard board with flat and hard chips, and a hard case. I have some unpleasant recollections of trying chips on flex harnesses in the defense industry, and the problems become non-trivial with bigger parts and shock forces coming into play, not to mention manufacturing costs.

We might be getting thrown off by the limiting context of a phone as we know it. A gently curved but still fixed display poses fewer problems in fabrication using current technology. Corning has recently announced production readiness for 3D-shaped Gorilla Glass, and Apple, LG, and Samsung are all chasing curved display fabrication and gently curved phone concepts today.

The real possibilities for smaller curved displays jump out in the context of wearables and the Internet of Things. The missing piece from this discussion: the touch interface. Flexible displays present a challenge well beyond the simplistic knobs-and-sliders, or even the science of multi-touch that allows swiping and other gestures. Abandoning the relative ease of planar coordinates implies not only smarter touch sensors, but algorithms behind them that can handle the challenges of projecting capacitance into curved space.

Atmel fully appreciates the magnitude of this revolution, and through a combination of serendipity and good planning is in the right place at the right time to make curved touchscreens for wearables and the IoT happen. With CES becoming an almost-auto show, it was the logical place to showcase the AvantCar proof of concept, illustrating just what curves can do for touch-enabled displays in consumer design. (Old web design axiom, holds true for industrial design too: men tend to like straight lines and precise grids, women tend to like curves and swooshes – combine both in a design for the win.)

The metal mesh technology in XSense – “fine line metal” or FLM – means the touch sensor is fabricated on a flexible PET film, able to conform to flat or reasonably curved displays up to 12 inches. XSense uses mutual capacitance, with electrodes in an orthogonal matrix, really an array of small touchscreens within a larger display. This removes ambiguity in the reported multiple touch coordinates by reporting points independently, and coincidentally enables better handling of polar coordinates following the curve of a display using Atmel’s maxTouch microcontrollers.

Now visualize this idea outside of the car environment, extended to a myriad of IoT and wearable devices. Gone are the clunky elastomeric buttons of the typical appliance, replaced by a shaped display with configurable interfaces depending on context. Free of the need for flat surfaces and mechanical switches in designs, touch displays can be integrated into many more wearable and everyday consumer devices.

Dr. Woo’s vision of flexible displays may be a bit early, but the idea of curved displays looks to be ready for prime time. The same revolution created by projected capacitance for touch in smartphones and tablets can now impact all kinds of smaller devices, a boon for user experience designers looking for more attractive and creative ways to present interfaces.

For more on the curved automotive console proof of concept, check out Atmel’s blog on AvantCar.

What do you think of the emergence of curved displays and the coming revolution in device design? How do you see curved touchscreens changing the way industrial designers think of the user interface on devices? Looking out further, what other technological improvements are needed?