How does the “main invention” concept apply in international patent applications?
The concept of “main invention” is crucial in cases where lack of unity of invention is found in an international patent application. According to MPEP 1875:
“The main invention, in case of doubt, is the first claimed invention for which an international search report has been issued by the International Searching Authority. The main invention, as viewed by the examiner, must be set forth on Form PCT/IPEA/405.”
This concept is particularly important when an applicant doesn’t respond to a lack of unity invitation, as the International Preliminary Examining Authority will focus its examination on the main invention. It ensures that at least one invention receives a full examination in the international phase.
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