Saint Gobain and Splanemann defend smart glass patent at EPO

The market for innovations in speciality glass for the automotive industry is fiercely competitive. There have been several recent patent disputes in this industry, such as Fuyao Glass vs Saint Gobain and ACG concerning head-up displays and Sekisui Chemicals and Kuraray concerning special films for car windscreens.

The current case revolves around Saint Gobain’s EP 3 774 417, protecting an “improved optical impression of a PDLC vehicle disc through a combination of dark inner and outer stacks”. The technology — known as smart glazing — is used in vehicle windows, particularly sunroofs. The glass is given a functional layer of PDLC (polymer dispersed liquid crystal), which can change electrically from transparent to opaque.

Boost for aesthetics

In many cases, these types of functional layer have a milky appearance when transparent due to the diffuse light scattering and are therefore aesthetically unappealing. The technology protected by EP 417 solves this problem by adjusting the light transmission of the vehicle windscreen above and below the functional layer.

The EPO’s Examining Division granted the patent in mid-2022. British glass manufacturer and processor Pilkington, which has been part of Japan’s Nippon Sheet Glass since 2006, filed an opposition in spring 2023. At the end of 2024, the Opposition Division rejected the opposition. The British glass manufacturer has now been unsuccessful in the appeal. The Boards of Appeal have upheld the patent in its entirety.

According to market analytics by Research Nester, the global automotive glass market will likely reach $55.5 billion by the end of 2035 due to rising car production and an increasing demand for premium sunroofs. Key players in the market are AGC, Saint-Gobain, Nippon Sheet Glass, Fuyao Glass, Guardian Industries, and Corning.

Trusted advisor

Dieter Gebauer

Patent holder Saint-Gobain Sekurit, a subsidiary of the French industrial group, once more relied on Dieter Gebauer of Munich boutique Splanemann. The patent attorney has a long-standing relationship with the French client and advises it on a variety of IP matters such as filing, prosecution, oppositions, nullity, and litigation. For example, he represented Saint Gobain in the recent opposition against a patent owned by Fuyao Glass and in a dispute with Asahi over glass-coating technology.

In-house patent attorney Andrew Stanley represented opponent Pilkington.