Double Patenting

A doctrine that states that an invention cannot be twice patented. An inventor cannot obtain claims in two patents directed either to the same invention or to an obvious variation of the same invention. Where the inventions are identical, the second patent is invalid. With respect to obvious variations, this rejection can be overcome by filing a terminal disclaimer which states that the second or any additional patents to issue will expire on the same date as the first patent, thereby eliminating any improper extension of the period of exclusivity resulting from the second or additional patents.

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