Taiwan: Claim amendment during a patent suit

Managing IP is part of Legal Benchmarking Limited, 1-2 Paris Gardens, London, SE1 8ND

Copyright © Legal Benchmarking Limited and its affiliated companies 2026

Accessibility | Terms of Use | Privacy Policy | Modern Slavery Statement

Taiwan: Claim amendment during a patent suit

A defendant in a patent lawsuit filed before the IP Court may, as a defence, challenge the validity of the patent in suit, and file a separate invalidation action against the patent with the IP Office. Although the IP Court and the IP Office often agree on patent validity in their decisions, there are sometimes disparities.

In a judgment issued in August 2015 in a patent infringement lawsuit, the Supreme Court expressed concern over the different stances adopted by the IP Court and the IP Office toward post-grant claim amendment.

The patent in suit is directed to a method for improving transmission of video data. However, in claim 1 of the patent, the preamble is followed by the expression "characterized in that" rather than "comprising the steps of" or the like. The defendant therefore argued that the patent in suit should be cancelled in view of the indefiniteness of the scope of claim 1 before the court and filed an invalidation action against the patent in suit. The patentee then filed a petition for post-grant claim amendment with the IP Office to replace "characterized in that" in claim 1 by "comprising the following steps".

According to the Examining Guidelines, the IP Office, if prepared to admit a post-grant amendment, should serve a copy of the amended claims on the invalidation petitioner for it to submit any observation thereon.

In this invalidation action, the amendment was indeed served on the invalidation petitioner, namely the defendant. The relevant documents were also entered into the IP Court's docket. In general, the IP Court would take this to mean that the IP Office is prepared to admit the amendment. However, in the infringement lawsuit, the IP Court opined that the claim amendment should not be admitted because claim 1 as amended was still indefinite. The patent was thus deemed invalid by the IP Court.

It was after the patentee filed an appeal with the Supreme Court that the IP Office formally allowed the post-grant amendment. However, the IP Office found that the claims did not involve an inventive step and cancelled the patent.

Noting the disparity between the IP Court and the IP Office regarding the admissibility of the claim amendment, the Supreme Court, in response to the appeal filed by the patentee against the judgment rendered by the IP Court, remanded the case to the IP Court for reconsideration, commenting that since the IP Office had served a copy of the claim amendment on the invalidation petitioner (the defendant), the IP Court's determination that the amendment was inadmissible was questionable.

This case sheds light on the need to review the claims of a patent and file any post-grant amendment, if necessary, when considering filing an infringement lawsuit in Taiwan based on the patent and to file the lawsuit after the amendment is granted.

Tung-Yang-Chang-Tony

Tony TY Chang


Saint Island International Patent & Law Offices7th Floor, No. 248, Section 3Nanking East RoadTaipei 105-45, Taiwan, ROCTel: +886 2 2775 1823Fax: +886 2 2731 6377siiplo@mail.saint-island.com.twwww.saint-island.com.tw

more from across site and SHARED ros bottom lb

More from across our site

The latest round of promotions has contributed to a 21% rise in partner headcount in the past two years, with business leaders eyeing litigation and the UPC
João Negrão, EUIPO executive director, is joined by a seasoned official to reflect on three decades of stories
Sim & San, which secured the $16m victory for their client, previously led Communications Components Antenna to a $26m damages win in 2024
IP litigator Ruth Hoy has led the London office since 2022
Emotional Perception AI is seeking more than £200,000 after the UK Supreme Court backed its appeal
Lawyers at Pinsent Masons discuss why the advent of ‘AI-free’ might be a crucial moment for brands seeking to protect their identity
Newly independent King & Wood has established offices in North America, while Mallesons has entered a ‘new era’ with a 1,200-lawyer firm across Australia and Singapore
Ryan Dykal and John Wittenzellner of Boies Schiller Flexner tell Managing IP what’s driving the firm’s patent litigation expansion
News of Dolby suing Snap over AV1 and HEVC patents and SCOTUS offering guidance on the liability of internet service providers were also among the top talking points
Arrival of Caitlin Heard will bolster the soon-to-be-created Ashurst Perkins Coie’s IP presence in the capital
Gift this article