In short, the company will use various sensors to determine the position of each display, including an accelerometer to calculate the angle of the screen. The abstract part of the patent describes the entire working principle in more detail:
A shell movement calculation including a processor, an accelerometer, two or more display devices determines a current user focus, the current user focus indicates the first display device, the second display device is turned off, and the accelerometer data detects the The mobile device has been rotated more than a threshold level, based on the gesture input to determine the current user focus has changed from the first display device to the second display device, that is, the second display device is turned on, the first display device is turned off.
Technically speaking, this solution makes sense for a device with a foldable display. There is no doubt that Microsoft will consider it for mass production at least some time in the future. However, there is no indication yet. Surface Phone will surface.
