Just at the moment when the outward appearance and construction of phones were beginning to stagnate, here comes another new tweak to keep us interested. LG Innotek today joins Fingerprint Cards, which unveiled its own solution earlier in the year, in announcing a fingerprint module that can be integrated under the same glass cover as a phone's display, obviating the need for a button. This will allow smartphone makers to have truly seamless designs while still offering the now-mandatory fingerprint authentication — and both companies expect devices with this new technology before the end of the year.

What's different about these new fingerprint sensors?

Traditional fingerprint readers have always required a discrete area just for their use. To integrate them most efficiently, smartphone makers have tended to build them into either the home button on the front, as Apple and Samsung do, or the power button on the back or side, as you'll find Google's Nexuses and Sony's Xperias. This year's new sensors offer the ability to integrate them into glass, which would remove any exterior sign of there being a sensor at all. Imagine Samsung's Galaxy S7, exactly as it is now, but with the home button being a capacitive key under the glass.

Is the benefit purely aesthetic?

No. LG Innotek points out that waterproofing a smartphone becomes significantly easier without a discrete button for the fingerprint reader. Plus the sensor itself is less susceptible to being scratched if it sits under the same tough cover glass as the display. Fingerprint readers have to be particularly robust, by microelectronics standards, because they sit on the exterior of a device.

Is there any downside?

Both LG Innotek and Fingerprint Cards promise to maintain the accuracy of current implementations — LG claims a false acceptance rate of just 0.002 percent — although the speed of recognition through the extra layer of glass might not be the same. That will have to be proven out by actual products, but other than potentially being slightly slower, the new glass-friendly fingerprint readers are basically as good as the button varieties we have today.

Who's going to use these new fingerprint readers?

Neither component supplier has announced any customers yet, but it's easy to offer up some informed guesses. Huawei has enjoyed great success being an early adopter of Fingerprint Cards' technology (2014's Mate 7 was one of the first devices to feature it), and it's likely to be at the head of the line for the upgraded 2016 version. Google has shown a recurrent antipathy toward physical buttons, so its next set of Nexus phones should also be considered likely candidates. It's worth noting that Fingerprint Cards acknowledged demand for glass-compatible fingerprint scanners six months ago, and back then it had already said it would provide such a solution this year — so hardware manufacturers have enjoyed enough lead time to factor it into their upcoming designs.

Who isn't going to use them?

Apple and Samsung. At least not the currently announced versions that are on the market. Fingerprint Cards doesn't even factor Apple into its "addressable market" forecasts for the year, with the Cupertino company relying on the in-house designs resulting from its acquisition of Authentec in 2012. Samsung also continues to work with Synaptics, though it might have wished it had completed the rumored (then later debunked) takeover of Fingerprint Cards when its tech wasn't as widespread as it is now.

Still, many technological advancements are developed in parallel, and the public announcements from LG Innotek and Fingerprint Cards can be taken as an indication of what's being worked on inside Apple's labs as well. The iPhone's home button is something of a hallowed territory, but Apple has shown its disdain for moving parts with the replacement of the moving MacBook trackpad with a more sophisticated haptic one. If the fingerprint scanner no longer requires the discrete button, that's another reason to go all capacitive and present an iPhone with a perfectly monolithic front.

Does this matter outside of phones?

Yes! Fingerprint reader makers anticipate the market outside of smartphones to be equal to that inside the mobile industry within just a couple of years. As far as they're concerned, every potential Internet of Things device is a potential fingerprint reader too. Want to secure your oven from misuse by the kids? Put a fingerprint reader on it. Same goes for the self-aware fridge or the TV remote control. The benefit of the new glass integration is that it makes the sensors easier to include in a design without spoiling the overall aesthetic — which is growing into a bigger consideration as companies like LG try to bring more luxurious and refined design to home appliances.

So... when?

The first phones with fingerprint scanners integrated under the display's glass will be coming out in the second half of this year. Some manufacturers could also opt to have a glass back and put the sensor at the rear. In both cases, there's high potential for cool new designs.