With bezels disappearing, OEMs are rapidly finding ways to shoehorn in-display biometric scanners for cheap, but be wary: They're not as reliable as dedicated capacitive sensors.
There was once a point in time when having a dedicated capacitive (reliable and secure) fingerprint sensor in a smartphone was theory and speculation. Turn back to circa 2012: Tech enthusiasts were reading articles on sites like this one where hot leaks were tipping off the plans that Samsung and other manufacturers supposedly had to include biometric security layers on their handsets. It wasn't entirely new tech at the time; the Motorola Atrix was actually the first to bring it to the table back in the wee days of Android in 2011. However, that was an optical variant, and those are now long outdated.
The iPhone 5s was the first to bring capacitive biometric scanning in September 2013, which proved a riotous success and paved the way for Android manufacturers to rethink the not-so-efficient optical variety. At that time, fingerprint scanners were a little too iffy to make or break a device as it was often easier to just stick to a PIN or password. You might remember that very recently, smartphones started breaking away from 2D facial recognition, which is basically a form of optical biometric security. It relies on what's essentially a photograph of the user's identifying traits be it finger, face or gesture.
This, of course, can be fooled by showing the respective camera a photograph of the user's face, or in more technical cases, a delicately lifted specimen of the user's fingerprint. Increasing cybersecurity concerns in recent years have spurred OEMs to push more compelling options to their devices in order to justify the flagship pricing that many of us feel there's no need to shell out for. As smartphones have become more refined on soft- and hardware fronts, it's now possible to purchase a sub-$200 handset and get a capacitive fingerprint sensor, 4-6 GB of RAM, an octa-core CPU, HD screen, pixel-binned camera layout and functional GPU for gaming.
In response, OEMs are pushing new forms of biometric security that capture data in three dimensions. This is basically what capacitive fingerprint sensors have already done for years. The issue is that rather than have a dedicated sensor for this purpose, they seem to feel that the tech is too old and needs some kind of upgrade for the sake of "new year, new phone" regardless of its functionality. With 3D facial recognition, we're also getting fingerprint sensors that are trying to stay one step ahead, and OEMs are doing this by building them straight into our displays. It's a sound theory — at least on the surface. We're seeing similar developments with in-display speakers. For the technical experts, we have just two questions: How well do these actually work, and what happens when you crack or break the screen?
In-display biometric sensors need some refinement before we're ready to see them become a widespread commodity. Currently, such sensors are not, in fact, an improvement over their traditional variants. On the consumer side of the fence, it appears to be a direct downgrade in all respects other than the wow factor, which gets old after the second or third time you pick the phone out of your pocket and require two or three individual attempts to gain access. It's particularly annoying because each of those attempts take longer than traditional capacitive fingerprint scanners, sometimes up to several seconds of holding, waiting and miserably failing. Who remembers the Galaxy S5's swipe scanner? It's that level of aggravating to use.
Our feelings are mixed about the matter, so we'll leave our readers with this: For the time being, don't make in-display scanners a priority on your next handset. Wait until the manufacturers have improved the tech before you leap at it. If possible, stick to a discrete sensor instead; they're tried and true by the test of time.