An anonymous reader quotes a report from Mashable: LG Innotek has developed a fingerprint sensor that's placed under a glass surface instead of in a physical button, the company announced Sunday. The new sensor could lead to smartphones that you can unlock by placing your finger on the phone screen. The LG-owned electronics parts manufacturer achieved this by cutting out a 0.01-inch thick slot in the lower part of a smartphone's cover glass, and then inserting a very thin fingerprint sensor into it. In other words, the sensor is still under the cover glass, but the slot moves the sensor close enough to the surface to read a fingerprint. That way, the sensor is protected from water and scratches, and can be installed anywhere under the phone's glass surface.