Glass warfare: Why unscratchable sapphire screens have Corning beating its chest


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Jan 30, 2012
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Everyone knows that fear-induced burst of nausea you get when your smartphone slips from your grasp and clatters onto the ground landing face down. You tentatively reach for it, bracing yourself for the horror of a shattered screen or a hairline fracture. You may feel that you’re lucky to get away with a few new scratches, but actually scratches make the glass much more likely to break the next time it has a hard landing.

That’s why sapphire glass from GT Advanced Technologies is generating a lot of interest. It’s much harder to scratch than Corning’s market leading Gorilla Glass (which is probably on your phone right now), but that’s far from the only difference between the two.

But the biggest news about sapphire hasn’t happened yet. Apple is reportedly investing in it, possibly as a screen for its next iPhone.
The idea that it may be used in the next iPhone screen elicited a strong response from Corning’s Senior VP, Tony Tripeny at a Morgan Stanley conference last week.

“When we look at it, we see a lot of disadvantages of sapphire versus Gorilla Glass,” said Tripeny. “It’s about 10 times more expensive. It’s about 1.6 times heavier. It’s environmentally unfriendly. It takes about 100 times more energy to generate a Sapphire crystal than it does glass. It transmits less light which … means either dimmer devices or shorter battery life. It continues to break. I think while it’s a scratch resistant product it still breaks…”

Corning the market
With a history that stretches back to 1851 and a current market cap of more than $27 billion, Corning is a proud company. It has lead the field in toughened glass since the 1950s, but it was Steve Jobs’ insistence on using glass instead of plastic in the original iPhone that led to the first mass production of Gorilla Glass.

Since then, Gorilla Glass 2 reduced the thickness and then Gorilla Glass 3 refined the original formula, to introduce better scratch resistance, greater strength, and reduced scratch visibility. Gorilla Glass is currently used in the majority of smartphones and tablets, although many manufacturers, like Apple and Sony, refuse to reveal what they use (it’s believed that Sony’s Xperia Z uses Dragontrail, made by Asahi Glass).

Apple’s glass
There has been a lot of conjecture about the glass that will be used in the next iPhone. Apple has stayed characteristically quiet on the subject, but we know a deal was penned with GT Advanced Technologies (GTAT) to supply “sapphire materials” for component manufacturing atApple’s new Arizona plant. This has naturally led to suggestions, such as this one at 9to5Mac, that sapphire glass will be used in iPhone 6 displays.

Much of the speculation has overlooked the fact that Apple already uses sapphire in the iPhone 5S for the camera lens and the Home button. It may produce more sapphire for a similar purpose in the iPhone 6, the next iPad, or perhaps in an iWatch. Sapphire is widely used in watches because of its scratch resistance.

Founded in 2006 with a current market cap of $2.3 billion, GTAT is an obvious underdog. It’s also engaged in polysilicon and photovoltaic businesses alongside the sapphire and it serves the solar, LED, and electronics industries, but it’s new to the smartphone market.

Sapphire’s strength
We got a demo of sapphire at MWC in 2013 and it was impressive. It’s the second hardest material in the world after diamond and the fact that it’s very hard to scratch means that it’s much less likely to break than competitors like Gorilla Glass or Dragontrail. GTAT claims that it’s around three times stronger, but it’s the scratch resistance that really matters.

A few months after we got that sapphire demo, Corning dismissed sapphire screens and began to point out potential problems with its manufacture, posting an article that claimed “sapphire not seen as major threat” and showing a video test that highlighted the superiority of Gorilla Glass in terms of handling pressure.

We should note that most smartphone screens are not broken by applied force. They get weakened by scratches and fractures and then break or shatter when dropped. Look at the scratch resistance of sapphire in this Aero-Gear video.

Corning will argue that sapphire may be more scratch resistant, but it’s also more likely to shatter when dropped. Sapphire is harder, not necessarily stronger. The counter to that argument is that sapphire is much less likely to get scratched and while a perfect Gorilla Glass 3 screen might survive a fall more often than sapphire, a scratched one definitely won’t, and it’s much more likely to pick up scratches. There’s obviously no consensus on which is less likely to break in the real world.

The Gorilla in the room
If Corning was really as comfortable as it suggests that Gorilla Glass is superior, then it wouldn’t be so critical of the competition. When Apple announced the deal with GTAT for sapphire supply, Corning’s stock fell. Forbes points out that Apple probably doesn’t account for a huge proportion of Corning’s Gorilla Glass profits and that could explain why the company doesn’t expect a switch to have an immediate impact on profits.

Cult of Mac does a good job of debunking Corning’s claims, noting that costs will inevitably fall as production ramps up and techniques are improved. You’d also be daft to bet against Apple’s ability to innovate and find solutions to the weight and light transmission challenges.

Whatever it says so publicly or not, Corning feels threatened. You may wonder why when you consider that the obscenely expensive $11,000 Vertu Ti is currently the only smartphone with a sapphire display. The shadow of Apple’s sapphire investment already looms.

The rise of sapphire
Reports like this one from IHS insist that sapphire demand among smartphone makers will increase, but it won’t necessarily be used in displays. Like Apple, LG used sapphire for its camera lens in the G2 and it’s likely others will follow suit.

Before you go, keep this in mind. Apple has already patented a method of fusing an extremely thin sapphire laminate sheet with cover glass, so it doesn’t need to produce pure sapphire displays to take advantage of some of the benefits. The bad news for Corning is that Cupertino doesn’t usually like to share.

Source: @digitaltrends
Nice article. To me it sounds like sour grapes from corning. If you confident in your product then allow your stats to do the talking. Am I saying sapphire is the next great thing, not sure. But I was impressed that the transparency was dead on with out any discoloration. Now how that will have an impact in direct sunlight or every day visual situations will he seen once it is in the hands of customers.
One person made a point in the iPhone 6 thread about sand (which I will include dirt and grime) how does it hold up to that. Because glass is only as strong as its weakest point which will be where a scratch is at. The other concern about glass are defects in the glass. Just the slightest defect (invisible to the naked eye) can result in a weak spot, as a result to heat, bending, and torque, that will make itself know whether it be from a drop or impact.

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