European Patent Office

Corning and Schott battle over flexible glass handset displays

Schott has overturned two patents for flexible glass owned by US glass manufacturer Corning at the European Patent Office. Now, the dispute over ultra-flexible glass between the two manufacturers is entering a decisive phase. The outcome of the case could significantly shape the production of flexible displays in mobile devices.

16 February 2021 by Mathieu Klos

Flexible glass At the EPO, Corning and Schott are undertaking a fierce dispute over flexible glass technology for mobile devices ©Alexey Brin/ADOBE STOCK

The European Patent Office has revoked EP 30 99 644, owned by US manufacturer Corning, which covers the production of flexible glass for use in mobile devices. Schott had previously filed an opposition against the patent. However, in January 2021 an EPO opposition proceeding revoked EP 644 because the patent and the invention were found to not meet European Patent Convention requirements.

According to JUVE Patent information, the EPO Opposition Division had doubts about the lack of reproducibility of Corning’s bendable glass. The US company can appeal the decision to the EPO Boards of Appeal.

Corning had already lost a second patent in May 2020, after Schott successfully challenged the grant of EP 30 99 643. In summer, Corning then filed an appeal against the decision of the EPO Opposition Division (case ID: T 1521/20-3.3.06). The office has not yet set a date for the oral hearing.

But a further opposition hearing by Schott against a third patent of Corning will take place on 26 April.  The patent in question, EP 30 99 642, protects the manufacturing of stack assemblies in bendable glass.

Flexible glass for the future

Bendable displays are considered a key technology for mobile devices. Korean handset giant Samsung Electronics was one of the first in the market to offer foldable mobile phones. Samsung’s Galaxy Z Flip and Galaxy Z Fold 2 phones use this bendable Ultra Thin Glass (UTG) developed by Samsung Display. Schott is the exclusive supplier of Samsung Display.

According to media reports, other handset makers from China and the US are currently working on foldable mobile phones.

Samsung Electronics is the world’s largest manufacturer of mobile devices, with Samsung Display belonging to the same Korean parent company. However, the two do not necessarily work together in device production. As recently reported by several media outlets, Samsung Electronics wants to develop its own display glass for future generations of its foldable smartphones. Here, the company wants to work together with US company Corning.

Flexible glass, Corning and Schott

Markus Rieck

Corning is best known for its very safe Gorilla Glass, used in many mobile devices. The US company started developing bendable display glass later than Schott.

Corning and Schott are not only fierce competitors in the field of bendable glass. Schott has also challenged another European patent owned by Corning, covering another technology. However, JUVE Patent is not aware of any further cases between the two opponents.

German and UK patent firms in the lead

Corning had previously filed its new flexible glass technology in the US, before bringing it over to Europe. The company regularly uses UK patent attorney firm Elkington & Fife for European applications, including EP 642, EP 643 and EP 644. Corning also works with a German and French patent attorney firm on EPO applications.

However, when Schott opposed the grant of EP 642, EP 643 and EP 644, Corning changed its advisors. Robert Sackin of UK firm Reddie & Grose now leads the defence of the patents.

Schott attacked the three Corning patents with the help of Markus Rieck, of German patent attorney firm Fuchs. The Frankfurt-based firm regularly works for the German glass product manufacturer. The latter also engages other German patent attorney firms for patent filings.

For Corning
Reddie & Grose (Cambridge): Robert Sackin (patent attorney)

For Schott
Fuchs (Frankfurt): Markus Rieck, Florian Rüssmann (both patent attorneys)
In-house (Mainz): Axel Curdt and Dagmar Burda (both patent attorneys)