Gorilla Glass maker Corning (predictably) slams sapphire, saying weaker and dimmer


In the tech equivalent of a turkey dissing Thanksgiving dinners, Corning SVP Tony Tripeny has criticized sapphire as a material for protecting phone screens, coming up with a whole list of claimed drawbacks, reports CNET.

We see a lot of disadvantages of Sapphire versus Gorilla Glass. 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 and our testing says that Gorilla Glass [can take] about 2.5 times more pressure that it can take.

Sapphire is far more resistant to scratches than Gorilla Glass, but Corning argue that it is more likely to be smashed.

Apple is expected to switch to a sapphire coating for the iPhone 6, manufacturing the material at the plant it jointly operates with GTAT in Arizona. While the material is indeed currently much more expensive than glass, it has been suggested that the costs could be substantially reduced with new production techniques.

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  1. alphabetize1 - 9 years ago

    I would just like a shatter resistant phone, I don’t really care what the material is.

  2. Fil Aperture - 9 years ago

    It would of course be surprising if Tony Tripeny (is he with the mob?) said something like this: Sh*t man, that sapphire stuff Apple is prepping kicks our Gorilla Glass ass! It’s way better and I think we can wrap it up here. In German they say: gefundenes fressen…

    • rlowhit - 9 years ago

      Corning’s response shows they are threatened so yes Tripeny is saying saphire is better.

  3. Tony C (@Muadibe10) - 9 years ago

    This isn’t just about sapphire versus Gorilla Glass. If you read up on GT Advanced Technologies and their current undertakings, you will see that there is a strong likelihood that solar charging technology will be part of that sapphire implementation.

    GT seems to have developed a process of using multiple layers of charging films, greatly enhancing charging efficiency. If this is what Apple is up to, the competition will look distinctly prehistoric – particularly since Apple has exclusive access to this new tech.


    • frankman91 - 9 years ago

      No phone screen will EVER be solar. The surface area is not even close to what is needed to charge a phone; not even close.

      Most solar panels are about 9 watts per square foot, or 0.0625 watts per square inch. The iPhone 5 is 4.87×2.31 inches, or 11.249 square inches. That would give you 0.703 watts per hour in direct sunlight. At that rate the 5.45 watt/hr battery would take 7.75 hours to charge if it were switched off, drawing no standby power at all, sitting in direct sunlight. That is also making a very incorrect assumption that batteries charge at 100% efficiency, which they defiantly do not. Realistically, a switched off dead phone would take close to or more than 10-12 hours to charge in the best of conditions.

      The brief window that the phone is in not in your pocket would do absolutely nothing. Even if that “40% efficiency gain” by that multi-layer cell is true, it’s still falling very short from what you would need and would be absolutely no benefit to adding a solar panel to a cell phone that was the size of the screen.

  4. Sounds like a thin layer of sapphire on top of Gorilla Glass is the best solution?

    • Robert Nixon - 9 years ago

      That would just make the screen dimmer, and the sapphire would still be prone to cracking, in which case you’d have to replace not just the sapphire, but the glass as well, since they would certainly be laminated together.

  5. scumbolt2014 - 9 years ago

    Sapphire isn’t going to be used for iPhione screens. I think this is Corning helping Apple throw everyone off track.

  6. How many times do I have to explain on this site, the sapphire is NOT for iPhones.

    • Chris Jackson - 9 years ago

      Then what is it for?

      • bballpants - 9 years ago

        iWatch. smaller surface, unscratcheable is more important than more light. Heavier doesn’t matter, in fact, it’s probably preferred as I like watches with a bit of heft. Economies of scale and research can develop further until sapphire BECOMES a suitable replacement for corning glass.

  7. I certainly think that Apple will not be putting your generic sapphire crystal onto the screen, they’ll be introducing something much better. “New production techniques” anyone?

  8. herb02135go - 9 years ago

    9 to 5 Mac PREDICTABLY Promotes Untried Technology Alleged to be Used by Apple!

  9. bballpants - 9 years ago

    “It’s about 10x more expensive.”
    So far. It’s not like Gorilla Glass was super cheap to make either. Apple. Economies of scale. Next.
    “It’s about 1.6x heavier”
    So? Still light.
    “Transmits less light. Breaks under less pressure”

    You know, all this means is that Sapphire isn’t ready for iPhone screens. It sounds ready for iWatch screens though. Less surface area means less weakpoints. Unscratchable for your watch is more important than allowing more light cuz you aren’t watching a movie on it!

    Plus it allows the technology to develop as iWatch iterates on its process.
    it’s a very apple thing to do.


Avatar for Ben Lovejoy Ben Lovejoy

Ben Lovejoy is a British technology writer and EU Editor for 9to5Mac. He’s known for his op-eds and diary pieces, exploring his experience of Apple products over time, for a more rounded review. He also writes fiction, with two technothriller novels, a couple of SF shorts and a rom-com!

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