Sony Interactive Entertainment has been granted a patent that describes an "electronic game cartridge," in what could hint what Sony might have in store for its next attempt at a handheld console.
The patent, which was granted to Sony by the Korea Intellectual Property Office in in the 19th of November 2018, includes not much information, besides some drawings of the device. It just mentions that it is made of synthetic resin and metal. It seems that the device has a connection at the bottom that could be used to communicate with a console.
Provided that the patent was filed in late November of 2017, it could be related to a future PlayStation console or it might not amount to anything.