Beauty, developed by Norwegian start-up Elliptic Labs, is a software-based ultrasound proximity solution that leverages smartphones' existing microphone and speakers to remove hardware-based—and often infrared-based—proximity sensor.

Now, the company said it is able to not only to remove the proximity sensor, but also hide the speaker behind the phone's glass screen. The new feat, marketed as "Inner Beauty," won the heart of Xiaomi and is what enabled the smartphone manufacturer to considerably extend the functional area of the screen on the newly released MIX smartphone.

During MIX's official launch, Xiaomi pointed out that by removing the holes typically required in the faceplate to accommodate for speakers and optical IR sensors, the new phone was able to have its screen extended, with a functional area covering 91.3% of the faceplate, compared to 67.7% for the iPhone 7 Plus.

Xiaomi MIX (cr) Figure 1: MIX features an extended screen, with a functional area covering 91.3% of the faceplate, compared to 67.7% for the iPhone 7 Plus.

Besides eliminating the unsightly holes on a phone's screen, Elliptic Labs claims its technology eliminates common issues with hardware proximity sensors, such as their unreliability in certain weather conditions or in response to various skin colours as well as dark hair. The new solution not only enables more screen real estate but reduces overall BOM costs by removing the hardware sensor.

In order to embed the speaker within the smartphone's body, behind the screen, Elliptic Labs helped Xiaomi co-design the sound transceiver inside the phone, so the sound would radiate through, in the front, Guenael Strutt, VP Product Development at Elliptic Labs, told EE Times Europe.

"We have to consider the geometry of the phone and there are a series of design requirements following some patented acoustic waveguide principles, so the ultrasonic transducer radiates towards the front of the phone," Strutt said.

This is an important design win for Elliptic Labs, Xiaomi aims the new phone at the Asian market. Last year, the smartphone OEM sold more than 70 million phones.

“We are thrilled to have our ultrasound proximity software featured in the new smartphone from world leader Xiaomi. Elliptic Labs is the only ultrasound proximity feature vendor designed into a tier-1 mobile handset,” said Laila Danielsen, CEO of Elliptic Labs. “This is a significant validation of our Elliptic Labs’ value proposition and we are confident this will pave the way for additional design wins for our innovative ultrasound proximity product in the coming quarters.”