How Super Strong Glass Keeps Your Smartphone Screen From Breaking

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So many consumer electronics have touchscreens these days, and we tend to take them for granted. Sure, they might break or crack, but they’ve gotten considerably more durable over the years. That’s thanks in large part to innovation by a team at Corning, manufacturers of Gorilla Glass.

You may not know Corning by name, but you’re certainly familiar with its accomplishments. The New York-based company produced the first glass light bulbs for Thomas Edison in 1879, pioneered Pyrex cookware in 1915, supplied the windows for the spacecraft Friendship 7 (which was flown by John Glenn for the first U.S. manned orbital flight), created missile nose cones during the Cold War, and was the site of Frank Hyde’s serendipitous discovery of high-purity fused silica in 1932 — the precursor to the optical fibers that connect us to the Internet today.

One of the company’s most recent accomplishments is the development of Gorilla Glass, which actually evolved from the 1962 invention of ChemCor. These days, consumers want more out of their smartphones and tablets — the increased demand also comes with a desire for thinner, lighter, more durable and aesthetically pleasing devices with perfectly sensitive touchscreens. That’s not to say that Gorilla Glass is shatterproof, but it’s definitely more resilient in the face of tumbles, water and general clumsiness than previous glass displays. Mashable spoke with Dr. Shashi Shashidhar, Corning’s business development manager, about Gorilla Glass’ history, how it’s made, how it’s tested and why it’s so strong.

Where You’ll Find It

Corning has a list on its website that names devices with Gorilla Glass, like the Samsung Galaxy S II, Sony Bravia TVs and the HTC Sensation, to name a few. Noticeably missing is any mention of Apple devices — Apple is notoriously secretive about their products and processes, but Gorilla Glass indeed protects the iPhone’s retina display. The Corning site says, “Your favorite device may include Gorilla Glass, even if you don’t see it listed.” Gorilla Glass can be found in 200 million devices, roughly 20% of the handsets in the world. It’s 20 times stiffer and 30 times harder than plastic, which explains its popularity in the CE world.

What Is It?

You’re probably wondering what makes Gorilla Glass so unique. Its durability comes courtesy of an ion-exchange process that leaves a thin layer of alkali-aluminosilicate compressed around the glass. This provides extra strength and protection for your displays, says Shashidhar. The glass belongs to a family of ion-exchangeable glass that was marketed as ChemCor in the 1960s, but the particular composition in Gorilla Glass has been improved to provide better protection and usability in consumer electronic. “We looked at why things break and what we need to do in this compression layer to give you a better glass. So even though it came from the 1960s, it was modified about five years ago to be adaptable for consumer electronics,” Shashidhar explains.

“When we were making ChemCor, the glass was pretty thick, and one of the things we had to figure out was how to make it work for a thin glass — ‘thin’ being one millimeter thick and below,” says Shashidhar.

Gorilla Glass creates an “armor that protects the glass from breaking, from scratches, and makes it less prone to breakage than normal glass,” he says. “The armor that we have is built is the strongest of any commercial glass.” It’s stronger because its compression layer is deeper than other glasses, allowing more flexibility and durability.

In addition to being strong, it’s also remarkably thin — from .5 mm to 2 mm — so the glass can replace acoustic glass and is superior to other glass in terms of power conduction and other technical aspects. Plus, its thinness means the devices it protects are lighter, which saves on shipping costs.

How Does It Work?

If you’ve dropped a smartphone a million times and seen it survive every one without suffering a spiderweb of glass shards, you’re probably wondering how Gorilla Glass is tested to endure such trauma. Shashidhar says Corning tests each product based on the way it’s used or creates a test that’s similar to the way it’s used. And if your phone’s screen has shattered into smithereens, it wasn’t sent back to the factory in vain — the damage helps Corning determine how to make glass even stronger.

“We look at all the broken phones and devices that come back, and we go through what’s called a ‘failure analysis’ to figure out exactly how the glass broke. We can look at all the glass pieces and tell that the glass started to break exactly at this point, and from here it spread out,” says Shashidhar, adding that most consumer electronics fall victim to a “sharp fall” – like dropping it on cement or some other high impact event. “Once we find out the cause, we do an indentation testing — we take a diamond tip and press it on the glass and apply a certain load … and see if it starts to break. The threshold at which it starts to crack tells us how much damage the glass can take. That’s a very effective test, and that’s a good way to see if a glass is good for a consumer electronics or not.”

For reference, Shashidhar says that if you do perform this indentation test on a window glass, you can apply about 400 grams — less than a pound — before it starts to crack. But Gorilla Glass can sustain up six kilograms before it shows signs of distress.

Shashidhar says that putting Gorilla Glass on consumer electronics “has really changed the user experience.” Before Gorilla Glass was there, you’d have to press “very deeply” on a plastic screen in order to register that you were touching it. But with the thin and sensitive Gorilla Glass, you barely have to apply pressure. Says Shashidhar, “I would say that getting the glass has really changed the aesthetic look of the devices and also the touch user experience.”

Disclosure: Gorilla Glass is used in some Lenovo products.

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