Scratch, Optics and Everything in Between

Corning has recently introduced Gorilla Glass DX products, specialist cover glass composites for smartphone camera modules. Smart Photography spoke to Scott Forester, Division Vice President, Business Director, Glass and Operations Council, Corning Gorilla Glass, who gave in-depth insights about the company, the product and material science. Please don’t forget to read the unabridged version of this interview on the Smart Photography website by scanning the QR code.

- Sujith Gopinath

Could you give us a background on the origins of Gorilla Glass?

It has been 13-14 years since we introduced Gorilla Glass, and it was really focussed on smartphones and cover glass. With the introduction of touch sensors and touch interface, you needed some material to protect the touch interface, and the obvious choice was plastic since it is cheap and clear. But with the first devices, people saw that it scratched, and scratched horribly. So, people started thinking about glass. But glass breaks. So how do we overcome that problem?

At Corning, we have been making glass for almost 170 years now and have seen lots of glass compositions. It is a challenge to make really tough thin glass. So, what we did is, we took a glass composition and made the ions in the glass, free ions, so that they could easily be exchanged in and out of the glass, and you put it into a hot bath with potassium salt. When you put a glass composition into this hot bath, the heat initiates an exchange of ions. What it does is, it takes the sodium ions out of the glass and replaces with potassium ions from the bath. These potassium ions are huge compared to the outgoing sodium ions. So, you effectively jam the surface of the glass with these big ions. And this creates a massive compressive stress on the surface of the glass which makes it really hard to break. To break a substance, you have to put in more stress than what is on the surface by bending till it eventually breaks. But this is glass that you can physically bend and yet won’t break because you are not creating enough stress to overcome the inherent stress that is holding it all together. Our innovation was to create glass that wouldn’t break as you drop your device since it flexes.

How did Gorilla Glass evolve over time?