There are lots of phones trying to maximise the amount of screen space they can fit into a regular-sized phone at the moment, despite the fact there are a bunch of important bits of hardware in the way. Hardware like the front camera, a speaker, and various different sensors. Some companies just deal with the fact they can't strip it all away and leave a bar at the top of the phone, like the Samsung Galaxy S9, while other opt for a notched display.
Other companies have been working on proper full-screen prototypes that move this hardware elsewhere, like the Vivo Apex's flip-up camera. That doesn't discount the need for an earpiece, which is kind of necessary to make phone calls. Samsung may have a solution, though, and that involves turning the display into a speaker.
The company showed off this idea in the form of a prototype at SID Display Week. The prototype itself was a phone-sized 6.22-inch QHD OLED display, dubbed Sound on Display, which Samsung had configured to act as a phone receiver. OLED Info notes that's similar to previously announced tech like LG's recently-unveiled crystal-sound OLED displays, and the tech used in Sony's XBR-A1E Bravia. Both of those are TV-centric, though, so Samsung's shown it can be shrunk down to a phone-friendly size.
It's not clear if and when we'll see this tech in a Samsung phone, since it's currently just a prototype. While similar tech is commercially available (for a hefty price, I might add), it's likely to be a while before Samsung is ready to implement it in a commercial handset. Don't get your hopes up for a Galaxy S10 debut, is what I'm saying.
Still, it's an interesting development, and could bode well for the phone industry's bezel-free future. It could easily be a step towards completely filling the front of a handset with screen, without having to resort to sliding mechanisms to hide key components while still keeping them accessible. [OLED Info via T3]