According to Wired, glass-maker Corning is “working on ultrathin, bendable glass that’s 0.1 millimeters thick and can bend to a 5 millimeter radius” that may be usable for smartphone displays within two years. Corning produces Gorilla Glass used in Apple’s iPhones, as well as in phones made by other manufacturers like LG, Asus, OnePlus, Nokia, Samsung, and more.
Developing Gorilla Glass that can bend or fold like the materials used for the Samsung Galaxy Fold display or other foldable phone concepts could address some shortcomings endemic to these early designs.
The folding phones you see in headlines and gadget blog galleries today rely on plastic polymers that may scratch easier or have other undesirable properties. Generally, smartphone-makers that have announced foldable phones have not allowed us to test-drive these phones, which is otherwise normal practice for traditional smartphone product unveilings. That may be primarily because the software is not there yet, but it could also be that the companies anticipate negative reactions to the plastic displays, which have not been standard in flagship phones for a decade.
That’s for good reason. Despite its colloquial reputation as something that shatters easily, glass can be remarkably resilient. The glass used in today’s smartphones is more scratch- and dent-resistant than plastic, thanks in no small part to the processes companies like Corning utilize. On the other hand, the plastic used for the Galaxy Fold and similar devices is likely to be a magnet for scratches and other blemishes. It runs the risk of developing a crease at the bend point over many thousands of uses, and it is likely to lead to other undesirable aesthetic outcomes. For example, maximum brightness may be lower in some cases than we see on today’s top, glass-screen-equipped smartphones.
Below: Samsung’s Galaxy Fold, unveiled at an event in San Francisco in February.
Wired spoke with John Bayne, Corning’s head of Gorilla Glass. Bayne had this to say about efforts to develop foldable glass for smartphone displays:
In a glass solution, you’re really challenging the laws of physics, in that to get a very tight bend radius you want to go thinner and thinner. But you also have to be able to survive a drop event and resist damage… The back of the problem we’re trying to break, the technical challenge, is, can you keep those tight 3- to 5-millimeter bend radii and also increase the damage resistance of the glass. That’s the trajectory we’re on.
Corning already has one bendable glass product called Willow Glass. However, it is unsuitable for smartphones. Willow Glass is produced by “dipping glass into a molten salt solution, where potassium ions enter and push out smaller sodium ions, creating a ‘compressive stress layer,'” according to Wired. But that process precludes use for digital devices like smartphones. Says Bayne:
In a display application, you’re putting transistors on the glass. Transistors hate salt: Sodium, potassium, anything from the salt family will eat away a transistor. For this family of glasses to work, you have to have these components in the glass that are incompatible with transistors.
Bayne and another expert Wired spoke with believe that Corning (or a competitor like ACG) will have foldable glass ready for use in foldable smartphones within a couple of years. But it’s a difficult journey. “We have glasses we’ve sampled to customers, and they’re functional,” Bayne told Wired. “But they’re not quite meeting all the requirements. People either want better performance against a drop event or a tighter bend radius. We can give them one or the other; the key is to give them both.”
Below: Huawei’s foldable phone, the Mate X.
Corning’s current 3-5mm bend radius would work for some foldable phone designs but not others. Devices with a flexible display on the outside of the device, like the Huawei Mate X, would be most appropriate, since those are around 11mm thick. Something like the Galaxy Fold—which has the folding display on the inside of the device—creates a much sharper crease than Corning’s flexible glass could currently stand up to.
As for Apple’s part in this, it’s uncertain whether the iPhone-maker will introduce devices with foldable displays. The technology is obviously still nascent as far as consumer applications go, and Apple is unlikely to make a move into this space until it’s clear there’s a market and the kinks have been ironed out. The company has filed multiple patents related to folding devices, but that doesn’t mean those concepts will make it to market. Some of Apple’s patents obviously do, but many of them don’t.
Apple invested $200 million in Corning in 2017, but that doesn’t mean that Corning is working exclusively with Apple, either. As noted, many other smartphone manufacturers rely on the company’s products as well.
All this is to say that device-makers that are facing consumer fatigue, slowing sales, and a lack of attention-grabbing hardware innovation in the smartphone space are looking for the next big thing. A lot of effort is being invested into foldable phones as that thing. But there’s a long way to go before there aren’t serious tradeoffs devices we’ve seen so far—and we’re not just talking about high price tags.
Ron Amadeo contributed to this report.