HAWAII—Qualcomm's ultrasonic under-display fingerprint sensor was one of the Samsung Galaxy S10's flagship features, but it had a rocky debut after it was shown screen protectors could cause it to malfunction. Today at Qualcomm's Snapdragon Tech Summit, the company announced a larger and potentially more secure sensor, the Qualcomm 3D Sonic Max. Will Samsung pick it up for the S11?

Most devices with under-display fingerprint sensors, such as the OnePlus 7 line, use optical sensors, primarily from a Chinese company called Goodix. Optical sensors take a picture of your finger. For the past several years, Qualcomm has been championing a different technology—ultrasonic sensing, which it says captures a more secure 3D image of your finger. The Galaxy S10 and S10+ were the first US phones to adopt Qualcomm's sensor approach.

But the best-laid plans often don't survive contact with the enemy—or, in this case, millions of fingers. After the S10's launch, users found that phone cases and screen protectors with an air gap between the screen and protector would cause the device to authenticate with any finger, something Samsung later solved with a software patch. A Korean telecom official cited in the Korea Times criticized the scanner's security, with an analyst raising the possibility that Samsung might move away from the ultrasonic scanners.

Under-display sensors also tend to be small, requiring precise positioning of a finger on a space that isn't clearly indicated. That can be frustrating for people who have trouble finding the fingerprint target.

This isn't stopping Qualcomm. At 30mm by 20mm, the new Qualcomm 3D Sonic Max is 17 times the size of Qualcomm's existing under-display fingerprint sensor, letting phones authenticate with multiple fingers at once, said Alex Katouzian, SVP and general manager for mobile at Qualcomm.

"It makes it much more accurate, capturing a much higher-resolution 3D fingerprint image which makes anti-spoof even better," Katouzian said. "We're going to be adding even more machine-learning capability into the fingerprint [sensor] because by now we have a large database of fingerprint [examples.] The user experience is going to be better, and the image quality is going to be better," he said.

The larger sensor will let Qualcomm target medical equipment, using the new sensor to detect blood flow and other aspects of health status, Katouzian said. But first, they'll have to convince their customers that the sensor is secure.

We're going to hear about a bunch of new Qualcomm technologies this week at Snapdragon Tech Summit. The upcoming Samsung Galaxy S11 and new LG phones will probably include many of them. We'll have to see early next year whether Samsung and LG take a flyer on Qualcomm's new fingerprint sensor.

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