Reissue of Patent Application
Often times patents get issued and they have errors and need to be corrected. Errors can be substantive or more typographical in nature and there are different mechanisms to address each one.
What does Reissuing a Patent Application Mean?
Whenever any patent is, through error, deemed wholly or partly inoperative or invalid, by reason of a defective specification or drawing, or by reason of the patentee claiming more or less than he had a right to claim in the patent, the Director shall, on the surrender of such patent and the payment of the fee required by law, reissue the patent for the invention disclosed in the original patent, and in accordance with a new and amended application, for the unexpired part of the term of the original patent. No new matter shall be introduced into the application for reissue. 35 USC 251(a)
No restriction on number of reissue patent applications. It’s possible that the Directory will approve several reissue patents – as there are no limits on the number of reissue applications may be given. There is a restriction on adding new matter and the claims’ scope may not be enlarged through reissue either.
Often times, for errors that are non-substantive and do not make the patent (as granted) partly/wholly inoperative, a correction can be made under what’s called a “certificate of correction” and the typo/clerical error may be fixed on the official final patent document. Note, that just because the final patent document has been updated, doesn’t mean it will be published in the Gazette.