Boréas Technologies has introduced the Boréas Piezo Haptic Engine (Boréas PHE) reference design for wearable designers. The fitness tracker module design helps designers leverage the performance benefits of piezo actuators to deliver high-definition (HD) haptic feedback in low-power, space-constrained wearables.
HD haptic technology is all about delivering a better user experience, ranging from communicating information without requiring the user’s sight or hearing and easy differentiation of haptic effects to creating immersive experiences when used with audio and video.
“The quality of haptic effects in smartwatches and fitness bands is vital to the user experience. This makes choosing a high‐quality haptic engine essential to customer satisfaction,” said Simon Chaput, founder and CEO, Boréas Technologies.
Chaput said the company is addressing the designer’s pain points in the wearable markets that demand strong haptic and user experiences in a better industrial design or lighter wearables. The result is the reference design that uses Boréas’ new PHE and piezo haptic driver with third-party piezo actuators and other components in the wearable device to create HD haptics that make the device feel like a high-end product.
The reference design is the same size as a typical fitness tracker found in the market, said Chaput. It shows designers how to integrate the piezo actuators and the Boréas piezo driver with the different components inside the device to generate the haptics, and then they work with their engineers to implement it into their end devices, he added.
“What it provides, if you do it well, is very strong haptics in a very compact form factor,” said Chaput.
Boréas offers the PHE as a performance boost over two legacy technologies – linear resonant actuators (LRAs) and eccentric rotating mass (ERM) motors. With LRAs and ERM motors, haptic performance is tied to their volume and mass, which makes them too large for a “satisfying” user experience in wearables, according to the company.
In comparison, the Boréas PHE uses a small integrated off‐the‐shelf piezo actuator and the mass of other internal components to generate the haptic performance, so it doesn’t need a bigger actuator, thus eliminating the size/power/performance trade-off seen in the legacy technologies.
Chaput explained that by using the mass of other internal components in the device to reduce the natural frequency, it was able to improve the haptic performance while using a small actuator. Typically, a large actuator is needed for a strong haptic response, which has been a pain point in space-constrained wearables where the battery takes up most of the board real estate.
The Boréas PHE integrates the company’s low-power piezo haptic driver, the BOS1901CW, in a 2.1 × 2.2 × 0.6 mm chip-scale package, an extension of the company’s flagship BOS1901 piezoelectric driver, first introduced in 2018. The family is based on the company’s
CapDrive technology platform, originally developed at Harvard University for ultra-thin cooling fans. CapDrive is a proprietary scalable piezoelectric actuator driver architecture that offers greater energy efficiency, low heat dissipation, and fast response times.
When compared to LRAs, the most commonly used haptic technology, in wearables, the PHE offers advantages in bandwidth, response time, power consumption, and size. The PHE offers stronger haptic effects over a wider bandwidth of 30-300 Hz, compared to small LRAs with a narrow bandwidth at >200 Hz. The PHE receives a Grade “A” from the Haptic Industry Forum’s HD specification over the 30 to 300-Hz bandwidth.
The PHE also offers faster response times for sharper and more realistic haptic effects in wearables with rise times of 2.25 cycles vs. LRA’s 11 cycles and fall times of <10 ms vs. LRA’s 80 ms.
In addition, Boreas said the PHE is up to 10× more power efficient compared to LRAs, which helps extend battery lifetime and it is housed in a small footprint with a 12 × 4 × 1.8 mm piezo actuator.
Power consumption is very important in these devices, and based on customers, the Boréas PHE also reduces power consumption by about six times compared to ERM, said Chaput.
With the lower power consumption, OEMs have a choice between increasing the battery life or using more haptics to create a richer user experience, which was previously not available to them.
The combination of technology benefits, including the wider bandwidth, enables a range of different haptics and uses cases from a wake-up alarm to a user heartbeat. The wider bandwidth gives you more playground to create engaging effects and complex sensations, Chaput added.
But there is still the challenge around the lack of piezo expertise by many OEMs, which has pushed Boréas into the design integration services arena over the past few years. OEMs are running fast trying to build their high-level product but none of them have become experts in piezos, said Stuart Nixdorff, senior vice president, at Boréas.
“We now offer these services as a common practice. It’s a little more than a reference design. It’s kind of like the old Intel days when they would provide a PC reference design, but they do all the design services work for you,” he added. “It’s not explicit design services but we’re working hand-in-hand with global tier one companies and doing the mechanical engineering for them and component tradeoffs and integration. That’s something that has really accelerated the market and is a change for our company.”
Nixdorff and Chaput agreed that design integration services is 100 percent necessary to help their customers. “If we provide a customer with just our chip and the actuator most of them don’t really know what to do with it or how to integrate that into a fully functional device,” said Chaput.
The Boréas PHE can be evaluated in the Fitness Tracker Reference Design. The PHE is compatible with third-party piezo actuators from leading companies.
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