Multitouch (well double touch) for the rest of us

22 October 2008

Chipmaker Atmel is banking on an avalanche of iPhone-like handsets that understand multi-fingered gestures. At the start of the year, Atmel decided to buy a UK-based startup Quantum Research Group that had already locked horns with Apple over the capacitive sensors used in the iPod, iPhone and the recent MacBooks.

A lot of QRG's business has been in home appliances - touch panels on the front of ovens and the like. Now, armed with QRG's own technology, Atmel is going after the handset makers who want touchscreens that understand gestures so they can fend off competition from the iPhone.

Chris Ard demonstrates the Atmel multitouch sensor

Atmel's controller divides the screen into 48 mini-touchscreens each functioning independently. Director of marketing Chris Ard reckons this works better than the existing methods which pick up touches on a single grid of X-Y lines. You can see how the controller registers Ard's touches on the laptop in the picture.

“We believe that we have unique IP on this. I think we are alone in individually addressing the touchscreen elements," Ard reckons.

However, perhaps more important than any claimed technical advantage is that the company has written software to decode common gestures such as pinching and wiping actions, similar to those found on the iPhone. However, the controller is limited to two discrete touches.

Asked whether Atmel is concerned about Apple's patents in this area - and bearing in mind Atmel now has a bunch of its own - Ard retorted that, right now, Apple has a bunch of patent applications. They have yet to be granted.

The controller is designed to work with two types of touchscreen. One is aimed at high-end handsets. The other is a cheep and cheerful single-layer single-touch design that is less accurate, largely because the links from the sensor elements to the controller have to wind around each other. A multi-layer design lets you have cross-overs.

“We think the single-layer version will be the most important part of the market because it will reduce the cost, taking it down to that of the resistive screen products,” says Ard. “It offers better light transmission than resistive and, because the sensor sits behind the display panel, you can’t damage it.”

Ard claimed the capacitive design will help with the design of thinner phones as the sensor is about 150µm thick versus the 500µm of the resistive touchscreen sensor array used on most smartphones today.