The following article appears in the journal JOM, 43 (7) (1991), p. 54. JOM is a publication of The Minerals, Metals & Materials Society

Post-Issuance Patent Office Modification of U.S. Patents

In general, the U.S. Patent and Trademark Office loses jurisdiction over a patent after issuance. By statute, however, the owner of a U.S. patent is permitted to make certain changes to the patent. In general, these changes involve efforts to revise the specification, delete or modify claims, or surrender all or portions of the patent term. In addition, there are certain actions which third parties can take with respect to a patent.

Among the actions which can be taken by the patent owner are a request for a certification of correction, the filing of a reissue application, the filing of a request for reexamination, and disclaiming or dedicating to the public all or a portion of a patent or patent term.

The owner of a patent may seek to reissue the patent to correct an error that occurred without deceptive intention. For example, the claims of the patent may be too narrow and, therefore, fail to provide the patentee with all of the protection to which he or she is entitled. Also, in some instances, the claims are deemed to be too broad and invalid. Narrowing such claims through a reissue application can serve to preserve validity.

There are a number of important limitations on one's right to obtain a reissue patent. The reissue route cannot be used to introduce new matter into the patent. The claims sought in the reissue must fall within the invention as described in the original patent. If the reissue seeks to broaden the claims, the application for reissue must be flied within two years after the date of grant of the patent. If the reissue seeks to narrow the claims, the application can be filed at any time prior to expiration of the patent. The reissued patent will expire 17 years after the date of grant of the original patent.

To protect third parties who, in reliance upon the coverage of the original patent, may have engaged in conduct that did not infringe that patent, but might infringe the reissued patent claims, the doctrine of intervening rights was created. This doctrine precludes the patentee from asserting that an article made, purchased or used prior to the date of issuance of the reissued patent infringes the reissued patent, if it did not infringe the original patent. The statute also provides that a court may, under certain circumstances, provide for continued manufacture, use or sale in situations where substantial preparation was made before the grant of the reissued patent.

Another major area of activity after patent issuance is the request for reexamination. This procedure is generally employed either by the patent owner or a third party who believes that—on the basis of some prior art or printed publication which was not before the Patent and Trademark Office during prosecution of the application that became the patent—one or more patent claims are invalid. When the owner seeks reexamination, it is generally either to obtain a ruling from the Patent and Trademark Office that the existing claims are valid over certain prior art or to revise the claims and obtain a ruling from the office that the claims, as revised, are patentable over the prior art.

When requesting reexamination, one must provide a written discussion of why the prior art is deemed relevant to patentability. The commissioner of patents must, within three months after receipt of a request for reexamination, determine whether a substantial new question of patentability affecting any claim of the patent is raised by the request. If such a question is deemed to exist, an order for reexamination will be issued.

If reexamination is ordered, the patent owner is given a period of time within which to file a statement regarding the issues and, if desired, to amend one or more patent claims and enter new claims. If the reexamination was initiated by a third party, the third party receives a copy of the owner's statement and is given the opportunity to respond to the Patent and Trademark Office with a copy to the patent owner. The patent owner has an opportunity to respond to any adverse ruling and, if unsatisfied with the examiner's decision, may appeal to the Patent and Trademark Office Board of Patent Appeals and Interferences. He or she may subsequently seek court review of the board's decision.

When the decision becomes final, the Patent and Trademark Office will issue a certificate that either cancels any claim determined to be unpatentable or confirms any claim determined to be patentable and incorporates any proposed amended claims or new claims.

When a patent issues with obvious clerical or typographical errors or minor errors which are not the fault of the Patent and Trademark Office, the patent owner may pay a fee and request that the office issue a certificate of correction. If the mistake was made by the Patent and Trademark Office and the error is clearly apparent from the record, the applicant may, without a fee, request a certificate of correction. In instances where the error is rather obvious and not material, the applicant may, in lieu of requesting a certificate, merely write a letter to the Patent and Trademark Office to identify the error and request that the letter be placed in the patent file.

Any person may cite, in writing, prior patents or publications that the he or she believes to have a bearing on the patentability of any claim of a patent. If the writing specifically sets forth the pertinency of the prior art to at least one claim of the patent, the Patent and Trademark Office will place the prior art and explanation in the file of the patent. If requested, the Patent and Trademark Office will withhold from the file the identity of the person making this submission.

In some instances, wherein one or more claims is deemed by the owner to be invalid, he or she may file a written disclaimer of such claim or claims with the Patent and Trademark Office. Such disclaimer will, in effect, remove the claim from the patent. Also, the patent owner may disclaim or dedicate to the public the entire term or any terminal portion of the term of a patent.

There are also statutory procedures for correcting an error in naming the inventor or inventors if such error occurred without deceptive intention.

With respect to many of these procedures, important legal judgements are frequently involved and action should be taken only after careful evaluation and appropriate counseling. In many instances, these procedures can be used advantageously to either bolster the position of the patent owner or to permit a third party, at minimum expense, to challenge the validity of patents or portions thereof.