Ultrasound tech builds touch interfaces - Embedded.com

Ultrasound tech builds touch interfaces


Whatever the material, whatever the material thickness, the California-based startup UltraSense Systems claims it can turn any surface into a user interface.

What if any surface — home door, car dashboard, oven glass — could be turned into a user interface? Mechanical buttons would disappear, and electronic devices would be waterproof. That’s the ambition of UltraSense Systems, Inc., a newly-formed company whose ultrasound sensor technology aims to create new touch experiences in the internet of things era.

UltraSense Systems (San Jose, Calif.) introduced what it claims is the smallest ultrasound sensor-on-chip for touch and gestures through any material and any material thickness. Dubbed TouchPoint and TouchPoint Z, its initial products are sampling now and are expected to be incorporated into several consumer and industrial devices in 2020.

Removing mechanical buttons

UltraSense brings together former InvenSense executives. Mo Maghsoudnia, a co-founder and the CEO of the new company, and Dan Goehl, chief business officer, worked together for about six years at InvenSense and saw that company rise to IPO. At the time, Maghsoudnia was vice-president of technology and worldwide manufacturing while Goehl was vice-president of worldwide sales.

When TDK Corp. completed the acquisition of InvenSense for $1.3 billion in May 2017, Goehl stayed for another 15 months. Maghoudnia, however, left to pursue ultrasound in medical. “He found that it would take a while to take off, and came up with the idea of using ultrasound as a touch user interface,” Goehl told EE Times. “That really was the genesis of UltraSense.”

Created in April 2018, UltraSense is now emerging from stealth mode. And because the smartphone market is a high-growth market, it has made mobile handsets its primary focus. “Adoption is relatively quick, and we are hitting the market at the right time with the launch of 5G technology, in particular millimeter-wave 5G,” said Goehl.

Image: UltraSense

As part of the process, the entrepreneurs went through their list of contacts, leveraged their network and started pitching their concept. “All phone makers were receptive, but they said the first thing they want to do is to replace the mechanical buttons.” A request that makes even more sense with the advent of 5G: “For millimeter-wave 5G technology, the industrial design of the phone is going to have to change because there are going to be 24 antennas in the phone just for 5G.” And these antennas will have to be able to work under glass and metal materials.

Sensing through all materials

A shift has recently occurred in the way users interact with their smartphones, smart home appliances and any other devices that have penetrated their daily lives. Digital has been replacing mechanical, and the move to virtual buttons and surface gestures is accelerating.

Immune to sensing through moisture, dirt, oils and lotions, UltraSense’s sensor is claimed to enable touch sensing through any material and any material thickness, including metal, glass, wood, ceramic and plastic.

Asked about any physical barriers, Goehl said the limit would be air and power. “We have designed our first products to be power efficient. We focus on the mobile environment, and we can go through 5 millimeters of aluminum, 5 millimeters of glass or 2 millimeters of stainless steel, the densest metal.” He continued: “Theoretically, with what we have and some other products coming up next year, power is not an issue. We can go through 20 millimeters of solid aluminum without any issue.”

Moving to the ultrasound technology itself, Goehl said: “We are transmitting an ultrasound beam through the material and we are looking for a change in acoustic impedance at the surface. As it reflects back into the sensor, we can see and interpret it as a medium or a heavy touch.” He further explained: “When we do a light touch, there is still air within the ridges of your fingerprints, but as we press harder, the ridges of your fingerprint deform against the surface material, and the air goes away. The harder we press, the more contrast we see.”

What if users carry their smartphone in their pocket? Could they trigger the sensor by accident? There is little risk, Goehl explained, because “we are able to understand the input material and reject that.” In the case of a cloth material, “we designed our ultrasound signal to dissipate in air, so when the phone is in your pocket, and it is rubbing against the cloth material, we can reject that pattern.” And many other patterns.

Sampling now

Image: UltraSense

No bigger than the tip of a pen (1.4×2.4×0.49mm in an optical LGA package), UltraSense’s TouchPoint is described as the smallest ultrasound sensor-on-chip. Consuming less than 20uA of power in always-on mode, it can operate independent of a product’s host processor with all the algorithm processing embedded in the sensor. It can be used as a standalone power button for wake-on-touch sensing, by powering on the entire product with a simple touch and as a multi-functional user interface using a series of taps, holds and swipes.

Basically, the sensor-on-chip is composed of an ASIC and a MEMS transducer. The ASIC, Goehl specified, includes the microcontroller, low dropout, memory, and analog front-end. The MEMS transducer is a piezoelectric micromachined transducer, or PMUT. “The recipe to do it is ours, but we can use both GlobalFoundries and TSMC to fabricate the transducer and the whole sensor-on-chip,” Goehl said.

Sampling now, the TouchPoint sensor-on-chip is ready for mass production. “ We have several design wins going on today wh ere phone makers have designed phones around our products to prove out the concept. We see some of those going into production in the second half of 2020.”

Executing on plans

Dan Goehl, UltraSense

Looking two to three years ahead, Goehl said he sees strong traction, not just in selling a sensor, but in selling a multi-functional user interface along with it. Starting in the mobile and consumer space, UltraSense sees prospects in the automotive sphere with “a lot of proofs of concepts going on with several automotive suppliers for various types of applications.”

In the automotive, he said other avenues could be pursued and synergies could be found between UltraSense’s technology and other touch interfaces, including haptic-enabled touch interface systems . For instance, “we can work with other materials and provide larger touch areas.”

UltraSense is not entering a virgin territory. A handful of companies such as strain-gauge sensor supplier Sentons and force touch sensor supplier New Degree Technology have been around for several years, “but our technology is very different,” said Goehl. Unlike strain gauge, force touch and surface acoustic wave solutions that have industrial and mechanical design restrictions (e.g. material thickness, integration complexity and production calibration time), UltraSense claims its TouchPoint solutions provide for minimal integration effort and mere seconds of production calibration. “The nice thing is that the market is ripe today; maybe a couple of years ago it wasn’t the right time.”

Today, UltraSense employs just over 20 people, but Goehl said it is in a hiring mode. “We will be ramping up production next year and in 2021 and we have some great vision for our product roadmap. We need engineers to be able to execute on our plans.”

>> This article was originally published on our sister site, EE Times.


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