[IP Practice Online] An enjoyable discussion of patent claim interpretation (Attorney Masakazu Kobayashi)
更新日：4 日前
Article information
Article type: Lectures and videos
Categories: Patents
Topics: Claim interpretation
First published on this website: 2026-10-07
Display and classification checked: 2026-10-07
[IP Practice Online] An enjoyable discussion of patent claim interpretation (Attorney Masakazu Kobayashi)
For example, “annular” in the claim phrase “an annular sealing member” is explained in the Kojien dictionary as “a ring-like shape,” “a round shape,” and so forth.
Focusing on “ring-like” and the technical significance of the “sealing function” described in the specification, a patent owner would argue that a shape making one circuit with its ends joined falls within the patent's scope even if the defendant's product is square. A concrete example, such as the Osaka Loop Line not being a perfect circle, may also inform interpretation.
The defendant, in contrast, would rely on the definition “a round shape” and circular drawings of the embodiments to argue that the scope is limited to circular shapes.
Likewise, even a seemingly clear term such as “rod-shaped” may give rise to a dispute over whether an L-shaped or conical product can be considered a “rod.” Here, too, interpretation looks beyond mere word definitions to the member's technical significance within the invention—for example, its function of “sliding along a straight elongated hole.”
Claim interpretation can be divided into three categories: (1) the meaning of terms, (2) the integral/separate-member issue (one member or a combination of multiple members), and (3) the whole/part issue (whether the entire item must satisfy a requirement or whether a part suffices).
If the wording alone does not resolve the dispute, the principal battleground moves to the technical significance, problems, and effects described in the specification.
Here, too, disputes arise over the level of generality at which to understand the technical significance—for example, a “sealing function” or the narrower “uniform sealing function.”
Numerically limited inventions are no exception. In a recent case involving a claim requiring “a molecular weight of 700 or more,” literal infringement was strictly denied for a defendant's product with a molecular weight of 699.9.
Even if the number itself is clear, ambiguity in the definition of what is measured (for example, “particle diameter”), the measurement method, product variability, and changes over time can become issues, making interpretation difficult.
In conclusion, claim interpretation involves constructing one's legal argument by drawing on the specification, drawings, prosecution history, and common technical knowledge, while recognizing the ambiguity of language.
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Original article (2025-11-30):
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Content changes and display maintenance are recorded separately.
2026-10-07: First published from the original LinkedIn post; categories, article information, and consultation navigation added.
2026-10-13: aligned related-article, topic-guide, and other managed links with the articles’ published URLs. The original article text was not changed.
