Over the years of covering Samsung patents for future foldable and scrollable displays I had begun to think that Apple didn't have much interest in this alternative next-generation smartphone category. But in the last year Apple has really cranked up their patent filings and clearly the race is on in this category between these two rivals and even extended to a few other competitors such as Google, Microsoft and Lenovo. Some of essential technologies to make foldable devices a reality will reportedly be ready by 2018.
Today the US Patent & Trademark Office published yet another patent application from Apple relating to foldable displays for bendable devices like an iPhone. According to Apple's filing, the iPhone's housing for a foldable design may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. This supports many recent rumors of Apple working on a glass or ceramic iPhone body for the future. Today's invention focuses on a unique lubrication system to support bendable displays so as to protect them from bending, twisting and folding over many years of ownership.
Electronic devices often include displays for presenting images to a user. Displays are typically formed from rigid planar substrates. Although satisfactory in many situations, rigid displays such as these may be difficult to integrate into certain devices, such as devices with bendable housings. It would therefore be desirable to be able to provide improved displays for electronic devices.
A Flexible/Foldable iPhone with Decoupled Display Layers
An electronic device may have a display. The device and display may bend about a bend axis. The display may have flexible layers to accommodate bending.
The display layers may include layers such as an organic light-emitting diode layer or other layer with pixels, a touch sensor layer, a protective layer with a polarizer, and a support layer. Lubrication layers formed from textured surfaces, slippery coatings, and lubricants such as oil or other liquids may be interposed between the layers of the display so that the display layers slip past each other during bending of the device and display. This helps prevent stress from building up in the display as the display bends and therefore allows the display to bend without damage.
The electronic device may have a housing in which the display is mounted. The housing may have a recess that receives the edges of the display or may have other structures that help retain the display within the housing while allowing the display layers to shift relative to each other during bending. Elastomeric gaskets and elastomeric lubricant retention structures may be used to mount the display layers in the housing and to retain liquid lubricant within the layers of the display. Anchors may be used to hold display layers together during bending. An anchor may, as an example, bridge a layer of liquid lubricant that is interposed between adjacent displayer layers and may overlap the bend axis.
Key Invention Point: The Display's Lubrication System
The bottommost of layers #24 noted in patent FIG. 8 noted above may be a supporting layer and may be formed from a material such as metal, plastic, or glass (as examples). This layer may provide the other layers in the display #14 with structural support and is designed to help the protect display from damage (e.g., damage from impact from a hard object, damage from inadvertent twisting, etc.).
To prevent adjacent thin layers of the display from sticking to each other and thereby increasing undesired stresses within the display layers, adjacent layers of the display may be separated by structures that allow the layers to slip past each other during bending.
For example, adjacent display layers may be separated by slippery structures. The slippery structures may include slippery textured surfaces, surfaces with slippery coatings, slippery materials (lubricants), and/or other non-stick structures.
Index-of-refraction-matching oil may be used to suppress reflections between adjacent display layers while providing lubrication. Decoupling the layers of the display from each other in this way allows the layers to slide over each other (e.g., one layer may slip past another with a sheering motion) to prevent excess stress from building up in the display. As a result, tight bends may be formed in the display without adversely affecting the display.
In Apple's patent FIG. 8 noted above we're able to see a cross-sectional side view of a set of adjacent layers with an intervening slippery layer #30 formed from lubricating layer #30' between coating layers #24' (e.g., slippery coating layers and/or textured coatings for retaining liquid lubricant).
Layer #30' may be oil (e.g., index-of-refraction matching oil) or other liquid lubricant, lubricating particles, lubricant having particles suspended in liquid, or other lubricant.
To help retain liquid lubricant within the gap between adjacent layers (e.g., to prevent liquid from escaping laterally), a lubricant retention structure such as structure #40 may be formed along the edge of the layers. The lubricant retention structure may be formed from silicone or other elastomeric material that can accommodate slippage between the layers without becoming detached from the layers.
Structures such as the lubricant retention structure may have the shape of a solid bead of elastomer that runs along the peripheral edge of the display or may, as shown in FIG. 8, have a partially hollow interior portion that serves as a reservoir 30R for liquid lubricant.
The iPhone (or other foldable device) may be provided with structures such as a bezel structure or other structures that help retain the display within the housing #12 and device 10 during bending and lateral movement of the layers.
When the iPhone is bent about bend axis #22, the layers of the display 14 may slip over one another. Edge features of the display such as structure #40 may be formed from a material that can deform to accommodate shifting of the relative positions of the edges of the layers.
Apple's patent application was filed back in Q3 2016. Considering that this is a patent application, the timing of such a product to market is unknown at this time.
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