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The priority date is the date used to establish the novelty and/or non-obviousness of a particular invention relative to art cited against patentability. A patent application which claims priority to an earlier parent application uses the original parent application’s date as its effective filing date.

Examples of patent applications which claim a priority date include:

  • continuation applications – divisionals, continuations, and continuations in part (CIPs);
  • domestic applications based on foreign/international filings – patent applications first filed in a foreign country, or as an international application (PCT), and then filed in the United States, may claim the foreign application’s filing date in as its priority date; and
  • U.S. provisional patent applications – a U.S. applicant may file a provisional patent application, and then file a non-provisional patent application within one year. A non-provisional patent application may claim the filing date of the provisional application as its priority date (effective filing date).

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