Kyoto District Court, 1996 (Wa) 1597 [Thermal Head]
更新日：2 日前
Article information
Article type: Case note
Category: Patents
Topics: Divisional applications
First published on this website: 2026-11-01
Display and classification checked: November 2, 2026
Originally published on Ameblo: 2025-06-04 (Japan time). Full English translation.
Kyoto District Court, 1996 (Wa) 1597 [Thermal Head]
*The patentee's arguments during prosecution of the parent of a divisional application were likewise not considered in construing the claim language.
“The prosecution history of the invention in the parent application may be considered only in exceptional circumstances where establishment of the patent right in the divisional application is closely related to the parent application, and reference to the parent's prosecution history clarifies the meaning of the specification or drawings attached to the parent application that already formed the basis for the divisional application at the time of division.”
(Excerpts from the court's reasoning)
Because the invention in the divisional application and the invention remaining in the parent after division are separate and independent, it is, as above, generally inappropriate to consider the parent invention's prosecution history in determining the technical scope of the divisional invention. (Statements made during prosecution of the parent invention cannot be regarded as statements about the divisional invention.)
However, the parent invention's prosecution history may be considered only in exceptional circumstances where establishment of the divisional patent right is closely related to the parent, and reference to the parent's prosecution history clarifies the meaning of the specification or drawings attached to the parent application that already formed the basis for the divisional application at the time of division. (In that situation, determining the meaning of the parent's pre-division specification also permits the meaning of the divisional invention described therein to be regarded as already clear at the time of division.)
Update history
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November 1, 2026: First published on this website.
November 2, 2026: Added article information, classification, topics, language navigation, related articles where the same case was confirmed, consultation guidance, and SEO. The original text and first-published date were preserved.
