Formed in Air | Display Legacy | Corning

Today’s interactive society is built on a foundation of glass – glass that’s flatter, more pristine, and lighter weight than most people ever thought possible.

One type of advanced glass, Corning® EAGLE XG® Glass, has made possible the proliferation of mobile phones, flat-screen televisions, notebooks and tablets, and other devices with brilliant LCD displays.

The manufacturing process that allows Corning to produce this glass – the fusion draw – is as remarkable as the glass itself. The process is a massive feat of physics, chemistry, and mechanics, with single sheets of thin glass forming in midair.

The idea of the fusion draw was born in the late 1950s. Corning was seeking a way to reliably make large, flat glass sheets in a way that could quickly and efficiently scale up to high-volume production.

Another glassmaking process was being developed by Pilkington Brothers in the United Kingdom. Known as the “float” method, it involved pouring molten glass onto a bath of hot tin. Other common methods required grinding and polishing to produce an optically clear window. This, in turn, required huge finishing plants and many workers.

Dr. Stuart Dockerty and Clint Shay of Corning devised a novel process that flowed molten glass into an open trough shaped like a large V. The trough overflowed, with gravity pulling the glass down either side. The streams met at the point of the V, fused in the air, then were drawn into a sheet.

The glass remained untouched until it was hard and cold enough to resist manufacturing damage. Ideally, the pristine surface would eliminate costly grinding and polishing.

As Corning developed the process in the 1960s, the auto industry sought a way to make safer, stronger windshields. Corning’s ability to chemically strengthen its fusion-drawn glass made it a contender for the business. But one challenge stood in the way: creating a glass with virtually no optical distortions in the glass.

Corning's team came close, overcoming significant technical obstacles. But Pilkington’s float method ultimately proved more efficient for this particular application.

The fusion draw equipment sat virtually idle for years. Meanwhile, leading electronics manufacturers were exploring the intriguing field of liquid crystal displays. At first, they were testing thin glass sheets for calculators and watches. But the potential for more sophisticated displays was vast.

Corning forged strong relationships with these innovators and rekindled its use of fusion draw to supply samples of alkali-free flat glass that wouldn’t damage semiconductors during LCD fabrication.

By 2006, Corning was the undisputed leader in the burgeoning LCD glass market. Then the fusion draw produced its most remarkable product yet: EAGLE XG glass, the industry’s first display glass completely free of heavy metals. 

Corning continuously improved the fusion process and today, EAGLE XG glass can be made thinner than a business card (.25 mm) and as large as two king-sized mattresses. The glass remains the standard for LCD panel manufacturers around the world.

The History of Glass...Continued