Dutch website LetsGoDigital has uncovered a patent for a foldable phone filed by Huawei in September 2017. The Chinese technology company seems to have developed a tablet-sized device which when folded would be the size of a regular smartphone. The central "gap" problem, created when a foldable dual-screen smartphone is opened up, has been addressed by making the device bendable.
https://www.notebookcheck.net/Patent-for-Huawei-foldable-smartphone-discovered.293554.0.html