Apple’s move toward a foldable iPhone appears to be continuing, with the company receiving a patent for “electronic devices with durable folding displays.”

Apple has long been rumored to be working on a foldable iPhone, with many experts and critics believing the company cannot ignore the form factor forever. In true Apple fashion, however, the company has been in no hurry to release its first foldable, waiting for the technology to mature so it can release a device that meets its exacting standards.

Apple’s summary provides some interesting details:

An electronic device may be provided with a foldable housing. The housing may have first and second portions that are coupled by a hinge for rotation about a bend axis.

A foldable display may be mounted to the foldable housing. The foldable display may have a display cover layer and a flexible display panel. The foldable display may bend around the bend axis. The display panel may have an array of pixels configured to display an image through the display cover Layer.

The display cover may be formed from a layer of glass. A recess may be formed in the layer of glass that extends along the bend axis. The recess may form a flexible locally thinned portion in the layer of glass that allows the glass layer to bend about the bend axis.To ensure that the display cover layer exhibits satisfactory impact resistance during drop events, corner portions and other edge portions of the display cover layer may have increased thickness relative to other portions of the display cover layer outside of the locally thinned portion.

The hinge and/or other structures in the display may be configured to help hold the display flat when unfolded during normal use, while causing the display to slightly fold about the bend axis when the electronic device is jolted during a drop event. This helps prevent the display from impacting a hard surface while fully opened.

Apple’s summary focuses heavily on addressing one of the biggest criticisms of many foldable devices, namely their fragility. Users have complained about screens becoming unusable after small drops, something Apple focuses heavily on in its summary.

Apple has a long history of incorporating fall detection measures. The company incorporated Sudden Motion Sensor technology in its laptops as early as 2005. The feature was designed to detect a fall and instantly park the heads of traditional spinning hard drives to prevent damage from the fall. A decade ago, the company received a patent for technology to help iPhones better survive falls.

In view of that history, it’s not surprising that Apple is focusing so heavily on helping a foldable iPhone survive a drop event intact.