The South Korean OLED specialist LG has reportedly patented what could be called a sliding TV. Its display is stretched across a new kind of moving armature that allows it to expand outward horizontally when activated. This screen also bends backwards around the edges of its frame, making it appear bezel-less on either side.
https://www.notebookcheck.net/LG-patents-what-might-be-the-world-s-first-expandable-edgeless-TV.546922.0.html