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

Two New Hampshire IP boutiques will soon merge to form Secant IP, seeking to scale patent strength while keeping a lean cost model
While the firm lost several litigators this month, Winston & Strawn is betting that its transatlantic merger will strengthen its IP practice
In other news, Ericsson sought a declaratory judgment against Acer and Netflix filed a cease-and-desist letter against ByteDance over AI misuse
As trade secret filings rise due to AI development and economic espionage concerns, firms are relying on proactive counselling to help clients navigate disputes
IP firm leaders share why they remain positive in the face of falling patent applications from US filers, and how they are meeting a rising demand from China
The power of DEI to swing IP pitches is welcome, but why does it have to be left so late?
Mathew Lucas has joined Pearce IP after spending more than 25 years at Qantm IP-owned firm Davies Collison Cave
Exclusive survey data reveals a generally lax in-house attitude towards DEI, but pitches have been known to turn on a final diversity question
Managing IP will host a ceremony in London on May 1 to reveal the winners
Abigail Wise shares her unusual pathway into the profession, from failing A-levels to becoming Lewis Silkin’s first female IP partner
Gift this article