Fingerprint scanners existed on smartphones even before Apple implemented them on the iPhone 5S. The problem was that the recognition was slow and inaccurate, as it required a finger swipe and it didn’t work at all angles.
The new sensor was capacitive and required only a light touch, no matter what the orientation of the finger was. Apple embodied the sensor in the home button, other manufacturers chose to place it on the back of the device or even on the right side, under the power button.
Now, LG has a new suggestion that can free smartphone designers from a headache. The company managed to place the sensor underneath the glass covering the display, thus making it easier for the designers to design sleek devices, more easy to waterproof as less number of cuts on the body of a device means less chance for water to find its way into the smartphone. It is notable that the recognition time of the new sensor is comparable with the current sensors being used, at 0.03ms.
There is no news on whether we will see LG devices with the new tech anytime soon, but the company said that there are currently talks with other manufacturers to commercialize the new sensors within the year. [source]