Foldable devices seemed like the way of the future as manufacturers like Samsung and Huawei rushed to get them into production. The high profile failure of the Samsung Galaxy Fold seems to have put a damper on that rush, however. IBM has filed a patent for a wearable that can be a smartwatch, a smartphone, and a tablet with a display that stacks away when not needed. The multifold display isn't anything like what Samsung used in its Galaxy Fold device.
Rather than being one continuous display, the IBM patent outlines a device that uses display tiles that stack into a smartwatch on the wrist and can be folded out into different configurations to give the user the screen size they want for the situation. The patent is titled "Variable display size for an electronic display device," and the application was originally filed in 2016.
About three years later the USPTO granted the patent on June 11, 2019. The renders here are from LetsGoDigital and are based on the data in the patent application. When folded on the wrist, the renderings show a wearable that has a much thicker than normal face. The screen tiles stack under each other in smartwatch configuration.
There are four compartments to the device in smartwatch mode with each of the compartments storing a pair of screen tiles. Each tile can be taken from the housing individually and measures 2" x 3". The design automatically changes from smartwatch mode to smartphone mode when four of the display tiles are used with a screen that measures 4" x 6". When all eight of the screen tiles are used, the device switches into tablet mode with an 8" x 12" screen according to the patent, but that seems incorrect as 8" x 6" appears to be accurate based on the renderings.
The tiles have no border meaning that the seams between them are thin enough as to create one continuous image. The renderings do show enough seams to muck up what you are looking at a bit. One mystery with the patent is how exactly the screen tiles fold out. It's not clear if this is some sort of automated mechanized action or if they are moved manually. The latter seems like the most likely situation.