Reissue applications are valuable tools for correcting defects in issued patents. Reissue applications are used to correct a wide variety of errors that are more substantive than those which may be corrected by simply requesting a Certificate of Correction. A patentee surrenders their patent, pays a fee, and then reissues the invention disclosed in the original patent with the defects corrected for the unexpired part of the term of the original patent.

As explained the M.P.E.P., the error upon which a reissue is based must be one which causes the patent to be “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.” M.P.E.P. § 1401. Applicants considering reissue applications, however, are often uncertain as to what constitutes a proper “error” for filing a reissue application.

The most common bases for filing a reissue application are:

  • the claims are too narrow or broad;
  • the disclosure contains inaccuracies;
  • applicant failed to or incorrectly claimed foreign priority; and/or
  • applicant failed to make reference to or incorrectly made reference to prior copending applications.

See M.P.E.P. § 1402 here.

Those errors may result from a wide variety of sources, including inadvertently obtaining a patent that does not cover all of the disclosed inventions the patentee intended to protect, drafting mistakes, or a deficient understanding of law or fact. An applicant may also not appreciate the full scope of the patent and may try to recapture unclaimed subject matter. This requires a request for a broadening reissue application, which must be applied for within two years from the grant of the original patent.

On the other hand, a patent can cover too much subject matter, such as an invention already known in the prior art, which would render the patent invalid. In these situations, the patentee may reissue the patent to narrow the scope of the invention. It’s important for applicants to recognize, however, that drafting choice is not an error simply because it is later regretted. Reissues granted when there was no error can be invalidated for being an improper reissue. Thus, it would be prudent for applicants to recognize the dividing line for an error versus no-error in a reissue application.