Law - PCT Invitation To Pay Additional Search Fees
An international application must relate to one invention only or to a group of inventions so linked as to form a single general inventive concept. If the International Searching Authority (ISA) finds that an applications lacks "unity of invention," it will invite the applicant to pay additional fees to have the additional inventions searched or to restrict the claims to one invention. The additional fees must be paid within the time limit fixed by the ISA, which time limit may be between 15 and 45 days.