Galaxy S10 has an ultrasonic fingerprint scanner. Here's why you should care

The Galaxy S10's built-in fingerprint scanner looks like the OnePlus 6T, but make no mistake. The flagship products Samsung Galaxy S10 and S10 Plus are the first phones to use Qualcomm's ultra-sound digital fingerprint technology, which uses sound waves to read your prints.

Linked to ultrasound in a medical office, this "Sonic 3D Sensor" technology works by bouncing the sound waves of your skin. It will capture your details in water, lotion and fat, at night or in daylight. Qualcomm also claims that it is faster and much safer than the optical fingerprint sensor that you have already seen in other phones. Indeed, the ultrasound reader makes a 3D capture of all the ridges and valleys that make up your skin, compared to a 2D image – essentially a photo – that an optical reader captures using light and not waves. sound.

The debate between ultrasound and optical fingerprint readers is at a time when biometric security is on the rise. On-screen fingerprint readers are a popular trend in phone design because they do not take up space on the phone's face and require less trial and error than a built-in sensor in the power button. phone case. This design fits well with the move to a fully screened face with barely visible glasses.

"Security and biometrics are integrating very quickly into mobile platforms," ​​said Alex Katouzian, senior vice president of mobile technology at Qualcomm, in December at Qulalcomm's annual technology summit in Hawaii. "This is the future of fingerprint technology."

The built-in ultrasonic fingerprint sensor in the screen layers replaces the iris scan as the biometric sensor of choice on the Galaxy S10 and S10 Plus in particular. (The Galaxy S10E is equipped with a capacitive traditional fingerprint reader on the power button.) The iris scanning has been around since the Galaxy S7, so the fact that Samsung is moving away from it is a surprise. Rumor has it that Google could incorporate 3D face scanning into the next version of Androidcalled Android Q.

For an animated explanation of the operation of ultrasonic fingerprint scanners, also be sure to watch the video of this story. In the meantime, here's what you need to know about the Galaxy S10 and S10 Plus built-in ultrasonic fingerprint reader.

What is an "ultrasonic" impression sensor?

The Sonic Sensor 3D fingerprint sensor developed by Qualcomm uses sound waves (it's the "sonic" part) to "read" your fingerprint when you unlock your phone. Nowadays, the trend is to integrate this fingerprint sensor under the display to unlock the phone by placing your finger or thumb in the center of the screen – it's also a built-in fingerprint reader on screen – but this type of sensor could also exist on the home button of a device. CNET saw a prototype of this ultrasonic sensor in 2015.

In this case, the ultrasonic sensor is integrated into one of the layers that make up the screen of your phone. When you place your finger on the target area, you touch the glass above your phone, not the sensor. But your skin sends a tiny electrical pulse that activates the sensor and allows it to do its job. It has been put to sleep, but by tapping the phone, you give it a helping hand to wake you up.

How exactly does the ultrasonic sensor work?

When your electrical signal reaches the sensor, it emits sound waves that bounce off your skin. The surface of your skin is not flat – your finger is a unique pattern of ridges and troughs, which allows fingerprints to be a useful form of identification. These ultrasonic waves bounce toward the processor, which maps your fingerprint based on the pressure picked up by the sound wave that bounces off your skin. Specifically, it calculates different voltage levels based on your peaks and valleys.

In a simplified example, assume that your peaks are 1 and your valley is 0. The ultrasonic sensor module can map this data to form a rich 3D image of your fingerprint details. The sound waves can also detect your blood circulation and reject an imprint of a severed finger. Do not be fooled by fake fingers or synthetic skin.

Ultrasonic or optical fingerprint reader: how is it different?

An optical fingerprint reader, such as that of Synaptics, a component manufacturer we first saw in Vivo phones – bounces light up your finger and back down to the sensor, which interprets the reading as a 2D image. It takes essentially a picture of your finger to determine the pattern of ridges and valleys. But experts say this approach is easier to deceive with a photo, a fingerprint transfer (for example, if someone raises your fingerprint) or a prosthetic footprint.

Qualcomm claims that its ultrasonic fingerprint sensor is powerful enough to get a reading of 4 millimeters in depth when it scans your fingerprint. It's at the level of the pores. We have not yet tried the Galaxy S10's ultrasonic fingerprint scanner, so we can not say for sure if that is true. But it is certain that all members of the security community will test it to the limit.

How are ultrasounds different from a fingerprint reader?

When you put your finger on a sleek reader located on the back, side or button of a phone, your fingerprints are captured by a capacitive fingerprint sensor. Yes, "capacitive" is the same term as used on your phone's touch screen, where your finger leaves a trace of electrical charge in trace status so that the screen can feel exactly where you touch.

This is the same case here. Throughout the scanner, the capacitors detect the location of the ribs of your fingers by measuring the electrical charge, then matching the pattern of these charges to your registered fingers.

What is the benefit of using it over facial identity and other face unlocking features?

Apple's facial identity uses a depth map composed of 30,000 infrared dots to map the contours of your face. Samsung used competing technologies to scan your irises, but removed it for new phones. Galaxy S10 phones use a third method in Google Android, which essentially involves taking a picture of your face. Facial IDs and iris scanning are considered safe enough for mobile payments, but the facial recognition option in Android Pie does not support mobile payments. It's there for convenience, but will not assure you a solid protection.

It's possible that Samsung had trouble making sure that a 3D front-facing facial scanner could work in time for the launch of its Galaxy S10. It is also possible that Samsung is linking its destiny to everything Google supports, so save money on an investment that could last only a few months. It would not be totally inconceivable to think that Samsung wants to save a Face ID style option for the Galaxy Note 10 release in August.

Whatever the plan, whatever the motivation, it is likely that the built-in fingerprint reader will remain in place for several generations, especially if it turns out as fast, convenient and secure as Qualcomm says.

Posted on December 4, 2018.
Update: February 21, 2019 at 10:01 am PT.