You can tell where the front facing camera is when you see the little round sensor near the top of the phone. Well....it looks as if Sony wants to take this a little bit further, as they have a concept in mind when it comes to the front facing camera. As a matter of fact, the sensor wouldn't even be located near the display or even at the top of the phone.
Sony would like to put the front facing camera behind the display. Sony has already filed a patent application for this concept and what Sony plans on doing, is not just adding one sensor behind the display, but four. The sensors will be the fingerprint sensor, proximity sensor, illuminance sensor and the camera sensor. Not only does Sony want to add four sensors behind the display of a smartphone, but they are also wanting to add "a material configured to visually obscure the sensor(s) when viewed through the light-transmissive display screen." What this means is, you shouldn't be able to see the sensors.
Looks like we will have to wait and see how this concept turns out.