Obviousness-type double patenting (ODP) attempts to prevent the term of a “reference patent” claiming an obvious variant of a parent patent to exceed the term of the parent. This fulfills the mandate of the patent statute of “one patent per invention.”
When issuance dates were compared pre URAA (1994), the need to file for terminal disclaimer (TD) in the later-issued patent was simple to resolve. But then came patent term adjustment (PTA) – time tacked onto an expiration date for PTO delay—and URAA (1994)’s twenty years from filing or priority date term –arrived to complicate determination of if and when ODP is an…
