How It Works: Vapor Deposition Process | Pure Glass Technology | Corning

在當時，透過這個似乎完全與玻璃無關的製程，康寧生產出一些全世界最純淨的玻璃。

氣相沉積是一種高溫製程，透過在生長表面上沉積一層又一層微小的玻璃微粒來製造玻璃，而不是冷卻熔融液體。

氣相沉積是康寧在光纖領域取得世界領先地位的關鍵。康寧還採用此製程生產其他高級玻璃技術產品，例如精密的望遠鏡反射鏡。

它代表了康寧豐富的材料知識、製程控制專業知識、尖端裝置設計和自動化技術的經典組合。

How it Works:

此製程包括多種形式，但康寧最常用的是外部氣相沉積 (OVD)，它可以在固態基質外部（或周圍）以極小的薄層「製作」新的玻璃。

例如，製造光纖時，從含矽（有時還包含被稱為「摻雜劑」的受控添加劑）的液體中生成蒸汽。燃燒過程將產生極小的氧化玻璃微粒（被稱為「煙灰」）和未燃燒蒸汽的混合物。蒸汽轉而會凝結在微粒周圍，然後進一步聚集，粘附在基質上。

蒸汽嚴密地沉積在長長的陶瓷餌桿周圍。一層又一層的蒸汽與玻璃微粒產生反應，最終形成超純淨的玻璃。取下餌桿後，完美的玻璃管（被稱為「預製棒」）將在極高溫度下被壓實，並拉制成細如髮絲的光纖。 

對於鏡頭、反射鏡和（多年來）美國太空船用的玻璃窗，氣相沉積「直接發生在玻璃」製造過程中，然後形成龐大、密實的整塊玻璃。製造大型望遠鏡反射鏡可能需要超過一年時間。

為什麼如此重要

對於光纖和望遠鏡鏡頭之類的產品，玻璃不能包含任何有礙光透射的污染物，哪怕是最小的污染物。氣相沉積可嚴格控制會進入蒸汽，進而融入玻璃的化學物質。最終製造出想像中最純淨、具有非凡適用性的玻璃。

觀看下面的影片（英文），了解氣相沉積製程的工作原理。

Why it's important

For products like optical fiber and telescope lenses, glass must be free of even the smallest contaminants that could interrupt transmission of light. OVD-formed glass allows very tight control of the chemicals that go into the vapor and, in turn, the glass. The result is some of the purest glass imaginable.

Pure silica glass, either with or without intentionally small amounts of dopants, is also able to withstand vast temperature changes with virtually no expansion or contraction. That's an essential quality for glass products that, for example, must perform reliably in outer space.

The process is also highly scalable, meaning that Corning can ramp up production of products like specialty optical fiber and make sure every spool is of the highest quality.

And OVD allows for very tight control of dopants added to the silica, which can result in the desired specific optical attributes in the glass – a precise refractive index for light going through fiber, for example. That superior process control capability, says Michelle, "allows us to achieve a comprehensive  product portfolio."

How it's evolved

Legendary Corning inventor Dr. Frank Hyde began the work in the 1930s that would eventually develop into vapor deposition. Corning revolutionized the process in the 1970s in creating the world's first low-loss optical fiber.

Continuous improvements over the years – most of a highly proprietary nature -- have enabled Corning to make the process increasingly efficient. That's one reason Corning is the leader in optical fiber manufacturing.

Why we excel at it

Although fiber makers can purchase manufacturing equipment on the open market, Corning designs and builds its own.

And the equipment's top-notch quality stems directly from Corning's fundamental understanding of the materials and the science – chemistry and physics – that combine to make the process.

Product demands, particularly in optical fiber, have challenged Corning to continue its investments in improving vapor deposition.

"We've had to grow our understanding -- and in turn, our capability for both our process control and our machine design – in order to meet market demands," said Gausman.

"Because of our legacy and decades of fundamentally understanding the work, we've been able to evolve the product portfolio. And that's what we'll continue to do."