LG Chem Achieves South Korean Supreme Court Victory Confirming Deuterium OLED Patent Validity and Paving the Way for Major Infringement Damages Against SFC
LG Chem has achieved a significant legal triumph after the South Korean Supreme Court rejected an appeal questioning the validity of the company’s deuterium OLED patent. The judgment handed down mid May confirms the legal standing of LG Chem in its monumental patent infringement lawsuit against SFC a Korean chemical firm jointly owned by Samsung Display and Idemitsu Kosan of Japan.
The patent in question pertains to a chemical treatment for organic electronic devices which involves using deuterated aryl anthracene compounds instead of ordinary hydrogen atoms. By substituting a number of the hydrogen atoms with their heavier isotopes, known as deuterium, the display panel driving voltage can be significantly lowered while simultaneously enhancing the brightness efficiency and lifespan of the screen.
This crucial intellectual property originally stemmed from a patent application filed by materials giant DuPont in South Korea back in 2011. The patent was officially registered in 2014 and LG Chem purchased it, along with 97 other patents from DuPont, in 2019 in order to gain a competitive advantage in the booming high end display materials sector.
The legal battle commenced in 2019 when Idemitsu Kosan and SFC filed separate invalidation petitions against the patent with the Intellectual Property Trial and Appeal Board. Both were rejected by the Board in 2022 which maintained the core patent’s validity. Idemitsu Kosan and SFC both challenged the Board's decision at the Patent Court, which again ruled in favor of LG Chem in 2024. Although Idemitsu Kosan withdrew its appeal to the Supreme Court in 2025, SFC decided to take the matter to the highest court which dismissed its appeal this month.
In the interim, LG Chem launched a correction trial against the patent to narrow its claims, preventing its invalidation while still attempting to cover the products sold by Idemitsu Kosan and SFC. The original patent’s broad claims were refined, including the deletion of some of the broader clauses and redefining the structural characteristics of the compound, specifically defining it as deuterated with at least 40% deuterium.
After successfully correcting its patent claims in 2023 while the appellate cases were still ongoing, LG Chem formally filed a patent infringement suit against SFC in 2024. Bolstered by the Supreme Court's final confirmation of the patent's validity, LG Chem is now demanding hefty compensation from its rivals. It is currently suing SFC for 30 billion KRW (about $22 million) in damages, as well as an injunction to halt the production and sale of the disputed materials, and the destruction of all of SFC’s existing inventory.
Now that the patent has been deemed valid, the subsequent part of the litigation will only focus on determining if the products sold by SFC are in violation of the defined 40% deuterium percentage. Experts are closely following the case, and it is predicted that the district court will issue its ruling on the patent infringement lawsuit between late July and early August.
Source: oled-info
