LAS VEGAS – Touchscreens have arguably become a dominant user interface for smartphones and tablets in recent years. In 2012 and beyond, touchscreens are becoming larger, thinner, faster, brighter and even stylus-enabled.
And of course, mobile device developers expect to design in all these advancements without paying for a potential increase in power consumption.
Atmel Corp. believes the onus of making that happen for mobile device guys falls onto the shoulders of touchscreen microcontroller suppliers, like themselves. “Our goal is to keep system designers unconstrained,” said Sherif Hanna, marketing manager at Atmel.
Atmel, which had zero revenue in the touch screen market until it acquired Quantum Research Group in 2008, doubled its touchscreen controller business from $150 million in 2010 to $300 million last year.
Jockeying for an even bigger market share, Atmel is rolling out at the Consumer Electronics Show Monday (Jan. 9th) its maXTouch S Series family, the company’s third generation touchscreen controllers, featuring two new home-grown technologies – “SlimSensor Technology” to combat display noise and “maXCharger Technology” to combats extreme charger noise.
Atmel engineers designed the new S Series touchscreen microcontrollers with three-goals in mind: significantly reduce the impact of system noise; enable slim sensors; support active and passive stylus. They claim to have achieved all three goals through the development of new analog circuitry, DSP blocks and firmware that are now all implemented in the new touchscreen microcontrollers.
Source: Atmel Corp.
A new breed of touchscreens
For most consumers, the responsiveness of a touch is one of the first things they notice when using a new touchscreen-enabled mobile device. Now, this “immersive experience in responsive touch” becomes even more critical, as more smartphones and tablets are increasingly morphing into a platform of choice for gaming, observed Hanna.
Unlike an e-reader on which a reader may touch only once when turning a page, gaming applications require much more active and repetitive contact. “That means a touchscreen microcontroller needs to crank out, constantly, display noise avoidance algorithm,” said Hanna. Unfortunately, that would only contribute to the higher power consumption.
In the new maXTouch S Series, Atmel’s design team added new hardware blocks to its touchscreen controller so that it can offload some of the heavy-duty processing tasks. “We are going for a happy middle ground for balanced hardware/software implementations,” explained Hanna.
A new class of touchscreens also means larger and thinner displays. Atmel claims its new touchscreen microcontrollers are designed to offer high electrode count to match display size and resolution, while supporting unshielded touch sensors.
Of the three new touchscreen microcontrollers, mXT1664S is ideal for products with touchscreens up to 17” diagonal. Unlike Atmel’s previous generation touchscreen controllers, which required system designers to use four of them to accommodate a larger screen to create 1386 nodes, the mXT1664S can support as many 1664 nodes as in a single chip.
Of all the new advancements, however, it is the thinness of new displays that are most taxing to touchscreen microcontrollers.
Thinner displays demand the thickness of the touch sensor stack to be reduced, and layers of glass and glues to be eliminated. Thinner displays use fully laminated, unshielded touch-on-lense sensors, displays-integrated on-cell sensors and ultra-thin film sensors.
These advanced touch sensor stacks are said to be up to 58% slimmer than their conventional counterparts, enabling system designers to reduce end-product thickness by more than 1mm.
“1mm may not sound like a lot,” said Hann, but when it is used in a large 10-inch display for tablets, for example, it translates into an end product that’s 30 percent lighter.
But of course, thinner displays only make the lives of touchscreen microcontroller guys more difficult, Hanna added, because microcontrollers need to work harder to overcome much larger display noise.
By offering full hardware acceleration of noise-cancelling functions, Atmel claims that the S Series can deliver much better noise immunity with twice as much improvement in responsiveness compared with the company’s current generation of maXTouch devices.
As mobile devices start using noisier high-pixel density displays, touchscreen microcontrollers must eliminate as much noise as possible. Atmel’s competitors resort to the use of listening channels (so that “they can pick up display noises that need to be subtracted”), or using touch sensing synchronization (“it locks you into a frequency”), Hanna explained.
Atmel’s Hanna believes that neither is a good idea. It’s because the use of listening channels requires antenna, which in turn can create additional interferences. The touch sensing synchronization is not ideal, either, because it prevents you from frequency hopping, an important feature to combat common mode noise from chargers, said Hanna. “Our technology makes it much easier for system designers to use new displays in their new mobile devices.”
The S Series also comes with “maXCharger Technology,” which Atmel describes “a novel blend of analog circuitry and intelligent algorithms that enables flawless touch performance with battery chargers that output up to 240V of common-mode noise.”
Atmel's maXCharger Technology uses high voltage and advanced algorithms to provide the equivalent of 14.4V touch sensor scanning on the mXT336S and the mXT224S, resulting in a significant improvement in signal-to-noise ratio in noisy conditions.
The mXT1664S, meanwhile, provides the equivalent of 24V touch sensor scanning with a corresponding SNR increase. “System designers can choose to engage this high-voltage scanning only when the charger is plugged into the system, as it is not needed when the system is running off the battery,” Hanna explained.
Last but not least, as far as the newest feature for touchscreens is concerned, Atmel’s Hanna predicts that “stylus will make a big comeback,” now that Google provides a native stylus support in Android version 4.0, codenamed “ice cream sandwich.” Ateml’s new S Series controllers are ready for it, by extending support to both active and passive stylus solutions, he said.
Atmel's maXTouch S Series devices are now sampling with lead customers. Production quantities will be available in Q1 2012.