A Korean company has developed an engineering concept for a phone with a flexible display that not only folds, but also stretches. It can turn a 5 inch phone into a 9 inch tablet, considerably larger than the current phones on the market. The company, Innosaem was founded by a former engineer of a Korean electronics company with a PHD in physics. He holds different patents for the idea.
The phone allows aspect ratios that are more suitable for video than current phones such as the Galaxy Fold and Huawei Mate X. By stretching the display, the aspect ratio comes closer to 16:9, which is widely used for tv and film. In the picture below, the upper right image is the aspect ratio of the Galaxy Fold and Mate X, whereas the lower image is the stretched concept phone of Innosaem.