Use-Based and Functional Patent Claims under Vietnamese Intellectual Property Law: Between Statutory Neutrality and Restrictive Examination Practice

Abstract

This article examines the treatment of use-based and functional patent claims under Vietnamese intellectual property law. Contrary to frequent assumptions in comparative patent discourse, Vietnamese patent law does not expressly prohibit such claim formats. However, in practice, claims framed primarily around intended use or functional effect are often rejected during substantive examination. This paper argues that the restrictive outcome observed in Vietnam is not the result of an explicit statutory ban, but rather an emergent consequence of the legal architecture governing clarity, sufficiency of disclosure, and the requirement to define a concrete technical solution. By distinguishing between law in books and law in action, the article situates Vietnamese practice within broader debates on claim formalism, legal certainty, and the limits of patent harmonization.

1. Introduction

In international patent practice, claim format plays a decisive role in determining the scope and enforceability of patent rights. Comparative discussions frequently contrast the relative flexibility of common-law jurisdictions, particularly the United States, with the more formalistic approaches observed in civil-law systems. Within this discourse, Vietnam is often characterized as categorically rejecting use-based or functional claims. This characterization, however, oversimplifies the legal reality.

This article seeks to provide a doctrinally precise account of Vietnamese patent law by demonstrating that no express prohibition against use-based or functional claims exists in statutory law. Instead, the restrictive outcomes observed in examination practice stem from structural features of the legal framework governing patentability and claim interpretation.

2. Statutory framework of Vietnamese patent law

The Law on Intellectual Property of Vietnam establishes three cumulative requirements for patentability: novelty, inventive step, and industrial applicability. None of these provisions addresses claim format as such. Likewise, the statutory provisions governing the contents of patent applications focus on disclosure obligations rather than linguistic form.

In particular, the requirement that the invention be disclosed in a manner sufficiently clear and complete for a person skilled in the art to carry it out functions as a central normative constraint. This requirement implicitly favors claims that articulate concrete technical features over claims that merely state an intended use or desired result.

3. Claim clarity, support, and the concept of a technical solution

Vietnamese patent law conceptualizes an invention as a technical solution to a technical problem. This conceptualization has significant implications for claim drafting. A claim that defines the invention primarily by reference to its function or use risks being perceived as describing an objective rather than a solution.

Functional language is not inherently impermissible. However, where functional features are not anchored to specific technical means disclosed in the specification, examiners may conclude that the claim lacks clarity or is insufficiently supported. In such cases, rejection is doctrinally grounded in disclosure requirements rather than in a categorical rule against
functional claiming.

4. Examination practice as law in action

The distinction between law in books and law in action is particularly salient in the Vietnamese context. Examination guidelines and long-standing administrative practice demonstrate a consistent preference for claims that enumerate structural or compositional features. Claims that rely predominantly on intended use or functional outcome are frequently challenged for failing to define the essential technical features of the invention.

This practice reflects institutional risk aversion and a desire for legal certainty in a system where patent enforcement remains relatively underdeveloped. By requiring concrete technical features, examiners reduce ambiguity in claim scope and facilitate subsequent validity and infringement assessments.

5. Comparative perspectives and mischaracterization risks

When viewed through a comparative lens, Vietnamese practice is sometimes portrayed as an outlier. Such portrayals risk mischaracterization by conflating examination outcomes with statutory prohibitions. Similar tensions between functional claiming and disclosure requirements can be observed in other civil-law jurisdictions, including China and certain applications before the European Patent Office.

Vietnamese practice should therefore be understood not as exceptional, but as representing a particular calibration of disclosure rigor and claim formalism within the spectrum of global patent systems.

6. Implications for international patent strategy

For applicants and practitioners, the Vietnamese approach underscores the importance of claim localization. Attempts to transplant use-based or functionally broad claims from other jurisdictions without substantive adaptation are likely to encounter resistance. Effective strategy requires rearticulation of the invention in terms of concrete technical features supported by the specification.

At the policy level, misunderstandings of Vietnamese law may distort debates on evergreening and patent abuse. Recognizing the doctrinal basis of examination practice allows for more nuanced and accurate policy analysis.

7. Conclusion

Vietnamese patent law does not prohibit use-based or functional claims as a matter of formal doctrine. The restrictive treatment of such claims in practice arises from deeper structural commitments to clarity, sufficiency of disclosure, and the definition of a concrete technical solution. Appreciating this distinction is essential for sound comparative analysis, effective international patent strategy, and informed discussions on the future of patent harmonization./.