Editorial: The World's First Smartphone With In-Display Fingerprint Scanner Is Official. Here Is How It Works

Back in June, at MWC 2017 in Shanghai, Vivo showcased a concept video (in partnership with Qualcomm) featuring a fingerprint scanner under the display of the smartphone. Later in December, Synaptics (which describes itself as "a human interface solution developer") announced that it had worked out the tech which was required to implement the in-display fingerprint scanner. Synaptics also announced that that it was working with a Tier 1 manufacturer to build the first smartphone with the new technology. Synaptics promised to show off the phone at CES 2018. Today, Vivo showcased the first smartphone in the world with a fingerprint scanner under the display. It's worth noting here that the phone shown off by Vivo today at CES 2018 was built in partnership with Synaptics. Qualcomm's solution of an in-display fingerprint scanner is due to be shown later this year.

The in-display fingerprint scanner -- termed as Clear ID by Synaptics -- is placed between the OLED panel and the mainboard. The Clear ID sensor detects the finger of the user from the space between the pixels of the OLED panel. The sensor uses the beam of the display to illuminate the finger and the light reflected from the finger is then captured by the optical fingerprint scanner. A fingerprint scanner has to perform two major tasks. The first one is to capture an image of the finger. The two most common ways to do this include optical scanning and capacitive scanning. The former is what Vivo has used and the latter is what we see in most smartphones - a dedicated fingerprint scanner button either on the front or back of the device. Once the image of the finger has been captured, the fingerprint scanner checks whether the pattern of ridges and valleys (the surface of your finger is uneven, that's why the ridges and valleys) in the image matches any of the fingerprint images registered before. If there is a match, the device gets unlocked.

Since the fingerprint sensor is hidden under the display, the screen shows you a graphical UI on where to place the finger. The placement of the fingerprint scanner is only shown when the fingerprint scanner is required to be used. At other times, the placement will be hidden and the screen will behave like a normal display. Vivo says that this fingerprint scanner is not just restricted to unlocking the device and can also be used to authenticate payments and for performing other secure operations. I'm guessing that Vivo will be working with developers to make sure that the graphical user interface of their apps includes some kind of screen wherein the user will be shown the placement of the fingerprint scanner.

The Clear ID sensor can only work with OLED panels and not LCD because LCD panels have a backlight which illuminates the entire display. As mentioned above, Clear ID scans the finger from between the pixels of the OLED panel and the backlight of an LCD screen won't give the sensor the space it needs to have a look at the finger.

Synaptics has assured everyone that the security of this fingerprint scanner is in par with that of other scanners. It still remains to be seen how such fingerprint scanners will hold up against dirty or wet fingers. The place where ClearID looses out though is speed. Synaptics says that ClearID requires 0.7 seconds to read a fingerprint. Although this doesn't sound slow, 0.7 seconds is 75% slower than the read times of capacitive fingerprint scanners on the OnePlus 5T and the Huawei Mate 10 Pro.

Vivo's Senior VP Alex Feng said that the phone is ready for mass production and it's availability details will be announced later. Smartphone company DOOGEE has also released a concept video showcasing a smartphone with an in-display fingerprint scanner and a notch like that of the iPhone X. By the way, it was believed that Apple would use an in-display scanner for the iPhone X, but we saw how that turned out to be and instead of a fingerprint scanner, Apple adopted facial recognition.

Although we are talking about futuristic tech here, Vivo's smartphone showcased today features the previous generation microUSB instead of the new USB Type-C.

This new technology will make it easier for smartphone manufacturers to further shrink the bezels. The only thing stopping us from seeing a completely bezel-less phone is the front facing camera, the proximity sensor and the earpiece. Will companies be working on getting that under the display? When do you expect for this to happen - 2018 or 2019? Let us know in the comments!


[Image credits - Vivo, John Kim/CNET & James Martin/CNET]

Krittin Kalra

Krittin Kalra is a 20 year old Android freak. Striving for passions, chasing down his dreams and living a life without regrets is his sole mantra. A bit moody, he also does custom ROM reviews for AndroGuider. Currently pursuing his B.Tech, he aspires to follow his heart.