Taking Touch Technology to the Next Level

 From touch to voice and gesture controls, there is no end in sight of the evolution of human-machine interfaces. Time and time again, it is a new user interface — whatever it might be — that has proven crucial in influencing consumer purchases.

There is no better example than Apple’s iPhone. Apple altered the competitive landscape of the mobile market by launching iPhones equipped with an innovative touchscreen that covers the entire surface of the device. Consumers ate it up.

Boréas Technologies, a 12-member startup based in Québec, is positioning itself to push touch tech a few steps further.

What if consumers could feel a localized high-definition (HD) sensation — vibration in smaller volume — simply by touching a small select area of the device?

The perennial pitch from the haptic community is that HD haptic feedback will eventually “let you feel the fabric of a shirt.”

Let that sink in for a minute.

Simon Chaput, Boréas’ founder and CEO, isn’t promising that we’ll get there right away. But when pressed, he said that the technology to achieve a high level of HD haptic feedback will be well-advanced within “the next five to six years” — available for proof of concept. The key to enable HD haptic feedback is the combination of touch sensing, haptic actuation, and driving IC based on piezoelectric technology.

Boréas is rolling out on Tuesday (Oct. 9) “the lowest-power piezoelectric driver IC for high-definition (HD) haptic feedback,” designable into wearables and other battery-powered consumer devices. Chaput claimed that Boréas’ BOS1901is “the only single IC solution available on the market today that can drive a piezoelectric actuator and sense it.”

Central to Boréas’ contribution to the industry is a dramatic reduction in power consumption and in the footprint of its piezoelectric driver IC.

Gu-Yeon Wei, professor of electrical engineering and computer science at Harvard University, told EE Times that opportunities for HD haptic feedback are “rich and diverse,” ranging from consumer products to enhanced gears for first responders and AR/VR game players. The new technology can add to audio and video “realistic sensations coming from touch,” he explained.

By simply pressing on a small area of the hard surfaces on a mobile device, users can sense localized vibrations, said Wei. This advance would allow system designers to offer “virtual buttons” or “virtual keyboards” on a smartphone or a tablet, for example. On a large display installed in vehicles like Tesla, a driver could feel his or her way down the road simply by running a finger or three over the screen without looking at it, he added.

Perhaps more exciting is the promise of genuine immersion that haptics could bring to gaming. Wei said, “Think about a haptic bodysuit and sense a shark brushing by you as you swim or wear a haptic glove and feel yourself hit a ball in an AR/VR game.”

It was in Wei’s lab where Chaput first began work on the technology that became Boréas’ BOS1901 haptic driver chip. During the interview, Wei called Chaput “the best engineer I’ve met … smart, disciplined, and very thorough.”

Electromechanical vs. piezoelectric
Notably, Boréas’ CapDrive technology platform, on which haptic driver ICs are built, is a proprietary piezoelectric driver architecture that can scale.

Boréas’ driver IC solution is taking full advantage of piezoelectric material. By combining piezoelectric actuators with Boréas’ piezoelectric driver ICs, the startup believes that its solution can milk HD haptic feedback, speeding response time to less than milliseconds and lowering energy consumption. None of this is available in legacy haptic solutions based on eccentric rotating mass (ERM) motors and linear resonant actuators (LRAs).

Boréas claims that its piezoelectric solution is the lowest-power haptic technology. (Source: Boréas)

Chaput explained that ERM vibration usually comes in game consoles such as Sony’s PlayStation and most smartphones. It offers no sensing functionality. LRAs are positioned as a mid-end haptic solution. LRA performs better than ERM, but the solution is “quite big,” said Chaput.

In contrast, piezoelectric uses thin materials and offers a very short response time. It is the only solution that offers integrated sensing functionality. Xiaomi once tried the piezoelectric solution for speakers but had implementation problems. The company is no longer using it, according to Chaput.

Specifically, Chaput said that Boréas’ piezoelectric driver IC solution consumes up to 10 times less energy compared to other solutions. It also offers six-times-faster response compared to that of leading competitors. Describing that latency as 300 microseconds, “That’s a very short response delay,” said Chaput. “It feels like almost real time.”

Piezoelectric’s Achilles’ heel?
Although the piezoelectric haptic solution is known for low power consumption, its Achilles’ heel is that it needs high driving voltage. Fifty to 200 volts are required to drive piezoelectric actuators, reducing the chance for piezoelectric to get designed into battery-operated devices, said Chaput. Boréas’ piezoelectric driver ICs, in contrast, are designed in the 3- to 5.5-V range.

Indeed, Boréas’ real invention is that his team built its driver “from the ground up to be highly efficient with piezoelectric actuators and with very low distortion,” according to Chaput.

With “the first low-power high-voltage piezoelectric driver for piezoelectric actuators” in hand, users of Boréas’ driving ICs could use any off-the-shelf piezo actuators in their haptic systems.

Boréas’ piezoelectric driver IC also offers “unique differential output,” said Chaput, to drive “one bipolar piezoelectric actuator or two unipolar piezoelectric actuators.” This reduces the number of drivers necessary for localized haptic applications, conserving precious board space.

This element could be critical in Boréas’ pursuit to enhance HD haptic feedback. Harvard’s Wei explained that, ultimately, HD haptic feedback needs an array of small haptic actuators that vibrate like “Morse code” in a coordinated fashion to transmit sensations like “feeling the fabric of a shirt.”

Competitive landscape
Boréas offers its driver IC on a hardware footprint of 4 x 4 x 0.8 mm. This isn’t exactly such a tiny IC, acknowledged Chaput. But as “a full system that combines both driving and sensing in one chip,” it is ideal for space-constrained mobile devices, he added.

To be sure, Boréas isn’t the only chip vendor working on piezoelectric-based HD haptic feedback. Competitors include Texas Instruments and Aito BV (Amsterdam).

Based on what Chaput’s team gleaned from data sheets available on competitors’ websites, he is confident that the BOS1901’s power consumption performance beats the leading competitor IC.

Note: Vdd = 3.6V, f = 200 Hz, C = 47 nF. Vdd is the power supply voltage, f is the output signal frequency, and C is the capacitance of the output load.

In contrast to TI or Aito, both of which add a discrete solution for electronic sensing or a discrete high-voltage driver to drive a piezoelectric actuator, “we offer much lower power and smaller footprint,” concluded Chaput.

As the startup launches the BOS1901, Boréas offers a plug-and-play development kit for interactive piezoelectric haptic feedback. Currently 15 companies are either developing systems or evaluating the BOS1901, according to Chaput.

Asked who will fabricate the BOS1901 by using which process node, Chaput declined to comment. But he added that Boréas has secured foundries that can scale its driver IC production to multiple million units.