Today the U.S. Patent Office published a divisional patent application of Apple's that relates to an iPhone or iPad having a foldable display supported by a foldable electronic device housing.

To clarify, a divisional patent application is a type of patent application in the U.S. that is filed when an earlier application, known as the "parent application," contains more than one invention. The divisional application is carved out of the parent application and focuses on a distinct invention disclosed in the parent application. In this case, Apple eliminated the part of the previous patent about another form of expandable display: the scrollable/Rollable display.

The divisional application is able to retain the original filing date and priority of the parent application, which can be advantageous for patent protection. It is often used when the parent application lacks "unity of invention," meaning it describes multiple inventions.

Today’s divisional patent application focuses on an electronic device that includes a foldable display supported by a foldable electronic device housing. First and second portions of the electronic device housing may be joined using hinge structures. The electronic device may have a flexible display such as an organic light-emitting diode display. The flexible display may overlap the first housing portion, the hinge structures, and the second housing portion. A flexible supporting layer such as a layer of sheet metal may be used in supporting the display and may overlap the hinge structures.

The hinge structures may include members that are configured to move relative to each other as the hinge structures are bent. In some configurations, hinge structures for the device include gear teeth, belts, and/or other movement synchronization structures. The moving members in the hinge structures may include bars and links with opposing curved bearing surfaces. Stop surfaces may prevent excessive rotation of the bars and links with respect to each other.

The bars and links or other moving members in the hinge structures may rotate relative to each other about virtual pivot points that lie outside of the hinge structures. The pivot points may establish a reduced stress plane (e.g., a neutral stress plane or approximation of a neutral stress plane). The reduced stress plane may lie within the flexible display. This may help reduce stress on the pixels or other brittle layers of the display module as the display is bent.

In some configurations, the hinge structures may include a sliding hinge pin support plate. A hinge pin that passes through the second portion of the housing may be supported by the sliding hinge pin support plate. The hinge pin allows the second portion of the housing to rotate relative to the plate and first housing portion. When the first and second housing portions are folded together, the support plate may slide relative to the first housing portion, thereby moving the hinge pin relative to the first housing portion. This helps to ensure that links in the hinge structures are smoothly wrapped around a curved surface on the second housing surface as the device is folded. A bent portion of the display may rest on an outwardly facing surface of the hinge structures when the display is folded.

Apple's patent FIG. 1 below is perspective view of an iDevice illustrating a folding point in the middle; FIG. 4 is side view of an iDevice with a foldable display; FIG. 8 is a cross-sectional side view of an illustrative electronic device with a folding display; and FIG. 22 is a perspective view of an iDevice in a configuration in which the hinge has been bent at a right angle.

Apple's patent FIG. 23 below is a perspective view of an iDevice in a configuration in which the hinge has been bent by 180.degree; FIG. 36 is a perspective view of a portion of the illustrative foldable electronic device of FIG. 35 showing how the hinge structures of the device may include the movable hinge plate and a set of hinge links; and FIG. 37 is a perspective view an iDevice in a folded configuration.

Two of Apple’s Inventors

• Yasmin Afsar: Hardware Engineer, Emerging Display Technology
• Michael Wittenberg: Senior Product Design Engineer