Corning exec criticizes sapphire crystal displays

Corning, the company that manufactures the ultra-tough Gorilla Glass that has equipped the latest iPhone models, doesn’t approve of the new sapphire screens which could be featured on the next iPhone.

Tony Tripeny, a senior vice president at Corning Glass, answered a question about the differences between Gorilla Glass and sapphire during the Morgan Stanley Technology, Media & Telecom Conference, via Seeking Alpha, on Tuesday.

Tripeny talked about the numerous drawbacks of sapphire, at least from the perspective of Corning Gorilla Glass.

“When we look at it, we see a lot of disadvantages of sapphire versus Gorilla Glass,” he said. “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 it means either dimmer devices or shorter battery life. It continues to break. I think while it’s scratch resistant product it still breaks and our testing says that Gorilla Glass, about 2.5 times more pressure that it can take than Sapphire on. So when we look at it, we think from an overall industry and trend that is not attractive in consumer electronics.”

Among advantages, Tripeny mentioned that sapphire could be “a little more scratch resistant” than Gorilla Glass.

The exec also talked about the production costs and lower manufacturing yield of sapphire glass, which are higher than in the case of Gorilla Glass.

“The formation takes about 4,000 times longer than Gorilla Glass at a significantly higher melting temperature. Its hardness makes machining more difficult and costly. Then the cost per unit increases exponentially because when you have defects in boundaries in the crystal growth process, you essentially cut them out and so unlike glass where we have developed technologies so that we can have very large pristine pieces of glass, when you have that on crystals, what you end up doing is always having a yield issue. So it is really those items that make things more expensive.”