Article 19, Paragraph 4 of the Enforcement Rules of Taiwan Patent Act provides that a technical feature in an invention which consists of a combination of multiple technical features may be expressed in “means-plus-function” or “step-plus-function” language. Such a claim shall be interpreted to cover the corresponding structure, material, or acts described in the specification and equivalents thereof. With reference to the provisions of 35 U.S.C. Section 112, paragraph 6 (now 35 U.S.C. Section 112(f)) and U.S. examination practice, Taiwan Intellectual Property Office (the “TIPO”) provides in the Taiwan Patent Examination Guidelines that a claim is deemed to be “means-plus-function” or “step-plus-function” expression if it meets the following three conditions: (1) the term ”means (or device) for...” or “step for...” is used to recite a technical feature; (2) such term must recite a specific function; and (3) such term shall not recite the complete structure, material, or action sufficient to achieve the specified function.
An administrative judgment rendered by the Intellectual Property and Commercial Court (the “IPC Court”) on October 15, 2025, Case No. 2025 Xing Zhuan Su Zi No. 16, addressed whether certain technical features should be determined as “means-plus-function language.” The patent at issue was Taiwan Invention Patent No. I629025 (the “'025 Patent”), which relates to a slide rail assembly applicable to servers. In the invalidation proceedings, the invalidation requester combined several prior references to challenge the inventive step of the '025 Patent. TIPO concluded that all claims lacked inventive step. After the patentee's administrative appeal was dismissed, the patentee filed the present administrative action.
According to public records, the patentee did not argue that there existed “means-plus-function language” during the invalidation stage, but then asserted that certain technical features in the '025 Patent claims should be interpreted as “means-plus-function language” during the administrative appeal and the subsequent administrative litigation. The patentee argued that these technical features included “means for…” wording, merely described specific functions, and did not recite sufficient structures; accordingly, the patentee contended that said features satisfied the requirements set forth in the above Guidelines. However, the IPC Court held that the specification of the '025 Patent, such as in the section describing the prior art, already recited a slide rail assembly in the prior art having the same function and the structure for achieving that function. Therefore, a person having ordinary skill in the art would have had an established understanding of the structure for achieving the function before the filing date. The IPC Court concluded that the relevant technical features in the '025 Patent already recited the structure for achieving the function, and thus did not satisfy condition (3) of the Guidelines; therefore, they were not “means-plus-function language.”
In addition, the IPC Court stated that, if the patentee's “means-plus-function” interpretation were adopted, claim 1 would be narrowed to the minimum embodiment as described in the specification. In that event, the technical features added by the dependent claims depending from claim 1 would be encompassed by claim 1, and such duplicative features would violate the conciseness requirement under Article 26, Paragraph 2 of the Patent Act. Moreover, this would eliminate any differences between the dependent claims and claim 1, which would also violate the principle of claim differentiation. For these reasons, the IPC Court rejected the patentee's argument that the relevant technical features should be interpreted as “means-plus-function language,” and held that the '025 Patent lacked inventive step over the prior art references.
As explained above, the IPC Court indicated in this case that, where a person having ordinary skill in the art, based on pre-filing common general knowledge (e.g., the prior-art discussion in the specification), can ascertain the complete structure of a component from the claim language, the claim may be considered to have recited the structure of that component. In addition, the IPC Court also examined the dependency relationships among the claims to assess whether construing the technical features as “means-plus-function language” would violate the conciseness requirement and the claim differentiation principle, in order to evaluate whether such a construction would be reasonable.
Because interpreting a technical feature as “means-plus-function language” generally narrows the patent scope by requiring the claim to be interpreted as covering the corresponding structures described in the specification, it is relatively uncommon for patentees to proactively argue that a feature should be interpreted as “means-plus-function language.” Nevertheless, when facing a patentability challenge and needing to adopt a strategy to narrow the claim scope, a patentee may attempt to interpret certain features as “means-plus-function language” as the patentee did in this case, and, during the invalidation stage, the patentee should also be mindful of timely filing a request for post-grant amendment as an alternative option (although the patentee in this case did seek post-grant amendment during the invalidation proceedings, such amendment did not involve the technical features or structures implicated in the above “means-plus-function language” dispute).