Closeup on Corning Glass
Based in upstate New York, Corning is a significant US player in the OLED display supply chain. It manufactures various types of durable, scratch-resistant, and specialty glass for both the cover and substrates that are integral to OLED displays. Corning has a storied history, having made the glass casing for the original Thomas Edison light bulb. More recently, Corning has invested heavily in R&D and is a leader in cutting-edge glass technology.
Corning’s most popular product is Gorilla Glass, which was developed specifically after Steve Jobs inquired about making a suitable cover glass for the original iPhone. Today, Gorilla Glass can be found on some 6 billion devices, from smartphones and tablets to wearables. Although Apple now wants to pursue microLED display technology, Corning still supplies to OEMs and name brands around the world, including Chinese phone makers Huawei, ZTE, and Xiaomi.
Let’s take a closer look at Gorilla Glass.
Gorilla Glass is a type of aluminosilicate glass that’s strengthened through a proprietary chemical process. But its main ingredient, like virtually all glass, is high-purity silica sand (typically >99.5% purity), which is basically silicon. The silica is mixed with some combination of aluminum, sodium, and magnesium.
It is difficult to know the specific suppliers of raw materials to Corning, but it is likely the company gets its silica from one of these leading industry players:
Sibelco, The Quartz Corporation, Nordic Mining ASA, Creswick Quartz Plt Ltd., Mineracao Santa Rosa, HPQ Materials, Lianyungang Donghai Colorful Mineral Products Co., Ltd., Momentive, Jiangsu Pacific Quartz Co., Ltd., and Kyshtym Mining.
A few of the companies operate in North Carolina, which boasts some of the highest purity silica in the world. As for the aluminum, sodium, and magnesium, these are abundant elements that are found and produced around the world.
Raw materials are shipped to Harrodsburg, Kentucky, where most Gorilla Glass is still made in a plant that was established in 1952 (Gorilla Glass is now also made in Corning’s Asia operations). Materials are mixed and melted in a high-tech oven in what Corning calls a “fusion draw process”: The glass forms and hardens below a trough without ever being touched by a human hand.
But, to achieve Gorilla-level strength, that fused glass then undergoes an ion exchange process, whereby it is soaked in a sodium salt bath. The extremely high temperatures of the bath allow sodium ions to escape and to be replaced by larger potassium ions. After cooling, these potassium ions are compressed much closer, creating additional rigidity in the glass.