The date on which a patent assignment of an inventor’s patent rights is made can have a significant effect on downstream prosecution and success of the application(s) directed to the invention.
During prosecution, the Examiner will almost always cite prior art against the application. This prior art can come from nearly anywhere. However, commonly-owned prior art can be avoided if it was commonly-owned before the filing date of an application. Thus, the relation of the assignment date and the effective filing date can be a critical factor in the abandonment or allowance of an application.
35 U.S.C. 102(b)(2)(C) states that a disclosure shall not be prior art against a patent if the “subject matter disclosed and the claimed invention, not later than the effective filing date of the claimed invention, were owned by the same person or subject to an obligation of assignment to the same person.” This rule excepts “commonly owned” prior art from being used against a person or company. Common ownership can come about in a number of ways. It can be the result of an explicit assignment agreement, an obligation to assign (such as might arise either explicitly or implicitly in the context of employment), or because of a joint research agreement.
Establishing common ownership can be an effective way to argue against both novelty rejections under 35 U.S.C. 102 and obviousness rejections under 35 U.S.C. 103, because 35 U.S.C. 102(a) defines what is prior art both for purposes of novelty under 35 U.S.C. 102 as well as for purposes of obviousness under 35 U.S.C. 103. If a document qualifies as prior art under AIA 35 U.S.C. 102(a)(1) or (a)(2), and is not subject to an exception under AIA 35 U.S.C. 102(b), it may be applied for what it describes or teaches to those skilled in the art in a rejection under AIA 35 U.S.C. 103. Conversely, if a document is excluded from consideration as prior art under 35 U.S.C. 102(b)(2)(C), it cannot be considered prior art for any novelty or nonobviousness purposes. Nonetheless, the disclosure might still be relied on by the Examiner to make a double-patenting rejection.
Common ownership must exist at the time the application under prosecution was effectively filed. I’ve talked previously about what an effective filing date is, but for short-hand purposes here, it is the earliest date on which a patent application was filed which disclosed the subject matter claimed in the current application. So, if the current patent application stems from a provisional application, and the provisional disclosed the subject matter now claimed, the common ownership must have existed at the time the provisional was filed to be able to invalidate that disclosure as prior art. Therefore, prior to filing, an assignment should be signed and dated (and preferably notarized). As a backup, having employment agreements that create an obligation to assign can help establish ownership should an assignment be forgotten.