MKS Instruments Inc. Loses Patent Infringement Case Against Sens4 A/S

News and Press Release

For Immediate Release

Hellebaek, Denmark – April 9, 2025: Sens4 is pleased to announce that the Maritime and Commercial High Court of Denmark (Danish: Sø- og Handelsretten) recently ruled in its favor in a patent infringement lawsuit initiated by MKS Instruments Inc. (Nasdaq: MKSI).

On April 9, 2024, MKS Instruments Inc. initiated preliminary injunction proceedings, alleging that Sens4 infringed Danish patent DK/EP 3781918. On November 20, 2024, the Maritime and Commercial High Court rendered its judgment, fully acquitting Sens4 of all claims brought by MKS Instruments in the preliminary injunction proceedings. MKS Instruments decided not to appeal the decision to a higher court, making the ruling final. Additionally, the court ordered MKS Instruments to pay compensation of EUR 296,560 to Sens4. On December 18, Sens4 appealed the compensation amount to a higher court, seeking an increase. The final ruling in this case took place on March 31, 2025, concluding the preliminary injunction matter.

"Winning this case is a significant and important victory for Sens4," says Ole Wenzel, CEO and founder of Sens4. He continues: "In our view, MKS Instruments’ allegations of patent infringement were entirely unfounded and based on a misunderstanding of both established technology and Sens4’s inventions and technology."

The case concerns a heat-loss Pirani vacuum gauge circuit design, a measuring principle originally invented in 1906 by Marcello Pirani. In 2018, MKS began to establish a patent family regarding a specific method of connecting the Pirani sensor wire to a resistor.

Sens4 has disrupted the vacuum gauge market in recent years with its record-breaking innovative products and a paradigm shift driven by advanced protective sensor coatings in MEMS Pirani gauges. These coatings have expanded the range of applications for MEMS Pirani sensor technology, which was traditionally dominated by convection-type vacuum gauges.

“As an innovative company, we are highly focused on creating new, unique solutions and improving the possibilities for the application of Pirani sensor technology. In that context, we are of course also very attentive to any inventions our competitors may develop," says Ole Wenzel. He continues: "Sens4’s focus is to deliver value to our customers through innovative products, short delivery times, fair pricing, and an unwavering commitment to the highest ethical standards in everything we do.”

On May 1st, 2024, MKS initiated a main action lawsuit at the Maritime and Commercial High Court of Denmark. This case also concerns patent infringement allegations and validity of MKS Danish patent DK/EP 3781918 and utility model DK 2024 00047. This lawsuit is still pending.

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