Latest patent pointing to a foldable iPhone is one that covers a slim but strong hinge
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Apple has been awarded a patent for a hinge that could end up on a foldable iPhone, a MacBook Pro, or on other Apple devices that require one. The patent is titled "Electronic devices with fiber composite friction hinges" and the innovation comes from the use of composite materials to create a stronger but not a bulky component. The patent states that "the fiber composite hinge may be formed from a fiber composite material such as carbon fiber composite material."
Apple patents a slimmer, but still strong hinge that could be used on a foldable iPhone
In the patent, Apple writes that "An electronic device may have a one or more hinges. For example, a folding device may have a first housing portion that is coupled to a second housing portion by a friction hinge. The friction hinge may include fiber-reinforced structures such as carbon fiber composite structures and other fiber composite structures. The use of fiber composite structures may help reduce hinge bulk while improving hinge performance."

Sketches from the patent
"If care is not taken, hinge structures may be bulky, weak, and prone to slippage," the patent states. "This can make it difficult to use a laptop computer or other electronic device into which the hinge structures have been incorporated." To reiterate, the goal of the patent is to create a hinge that produces less bulk but still improves the performance of the hinge.
"A friction hinge arrangement may be used...so that the lid stays in place after the user has adjusted the angle of the lid as desired. As another example, a friction hinge may be used...so that a user can adjust the pressure." Devices mentioned in the patent include "cellular telephones, tablet computers, laptop computers, desktop computers, head-mounted devices, handheld controllers, finger devices, wristwatch devices, other wearable devices, keyboards, computer mice, remote controls, speakers, accessory displays, accessory cameras, and/or other electronic devices."
Apple has filed patent applications for other components needed for a foldable iPhone
A foldable iPhone seems to be in development. Recently Apple filed a patent application for a foldable battery that we would expect to see powering such a device. Earlier this year, TF International analyst Ming-Chi Kuo said that Apple will ship 15 million to 20 million foldable iPhone units in 2023 equipped with 8-inch foldable OLED panels created by Samsung.
At the time, Kuo discussed why he thinks that Apple, although late to the party, will end up becoming the winning phone manufacturer in the foldable market. "At present, the product position of foldable smartphones is mainly to integrate the smartphone and tablet. But we believe that the foldable smartphone is only one of the applications of the foldable design," Kuo says.
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