Apple has won a Patent relating to Future Foldable Displays that use a Polymer Filler to support the bendable portion of the display
Today the U.S. Patent and Trademark Office officially granted Apple a patent that relates to one aspect of their future foldable display technology.
Apple's granted patent covers an electronic device that may be provided with a foldable housing that allows the device to fold and unfold about a bend axis. A flexible display may be mounted in the foldable housing. The flexible display may have an array of pixels forming a display panel. The display panel may be configured to bend along the bend axis as the device is folded.
The flexible display may have a display cover layer that overlaps the display panel. The display cover layer may be formed from a layer of glass. A groove-shaped recess may be formed in the layer of glass that runs parallel to the bend axis. The recess forms a flexible locally thinned portion in the glass over the bend axis that allows the display to bend about the bend axis.
Polymer may be placed in the recess to help planarize the inner surface of the display cover layer. Stiffening structures such as glass strips and/or glass beads of one or more diameters may be embedded in the polymer to help stiffen the surface of the display cover layer in the locally thinned region so that the outer surface of the display cover layer is not too easily deformed by external pressure from an object such as a stylus. While supporting the outer surface of the display cover layer, the stiffening structures allow the display cover layer to bend satisfactorily about the bend axis.
Apple's patent FIG. 2 below is a perspective view of an illustrative electronic device with a foldable display. The device could be an iPhone, an iPad, a laptop and more.
Apple's patent FIG. 7 above is a cross-sectional side view of an illustrative locally thinned display cover layer with a polymer filler having embedded particles.
Further, as shown in FIG. 7, stiffening structures #60 may be incorporated into polymer #50 within the recess under thinned portion #44 of display cover layer #14CG. The particles may be spheres or particles of other shapes and may be formed from a material such as glass with a modulus of elasticity that is greater than that of polymer #50 (e.g., particles #60 may be glass beads). This stiffens the polymer and help prevent the portion of surface 40 that lies above thinned portion 44 from being too easily depressed (e.g., too easily locally deformed inward) due to pressure on surface 40 from the tip of a stylus or other external object. At the same time, because particles #60 are not directly connected to each other by any rigid structures (e.g., because there is a portion of polymer #50 between adjacent particles), particles #60 are free to move relative to each other while polymer #50 is flexed. As a result, layer 14CG and polymer 50 may still bend freely about bend axis #28.
To review the full details of this invention, check out granted patent 12114451.