What is the relationship between priority claims and the written description requirement?
Priority claims, whether under 35 U.S.C. 119 or 35 U.S.C. 120, are closely tied to the written description requirement. According to MPEP 2163.03:
“Under 35 U.S.C. 119(a) or (e), the claims in a U.S. application are entitled to the benefit of a foreign priority date or the filing date of a provisional application if the corresponding foreign application or provisional application supports the claims in the manner required by 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph.”
Similarly, for domestic priority under 35 U.S.C. 120:
“Under 35 U.S.C. 120, the claims in a U.S. application are entitled to the benefit of the filing date of an earlier filed U.S. application if the subject matter of the claim is disclosed in the manner provided by 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph in the earlier filed application.”
In essence, to claim priority, the earlier application (foreign, provisional, or U.S.) must provide adequate written description support for the claims in the later application. This ensures that the applicant had possession of the claimed invention at the time of the earlier filing.
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