Proofreading, Errors, and Certificate of Correction

After a patent issues, it is the patent owner’s choice as to whether or not to have the issued patent proofread. Most patents have at least some errors. Although the figure may be exaggerated, it has been reported that "documented studies have demonstrated that up to 94% of the granted U.S. patents require corrections to be filed."

Although some of the errors may be caused by the applicant (applicant errors - 35 U.S.C. §255), some errors are caused by the U.S. Patent and Trademark Office (PTO errors - 35 U.S.C. §254). Until relatively recently, when a patent issued, someone at the U.S. Patent Office would review the entire patent prosecution history and manually re-type the patent. Of course, the re-typing generally introduced typographical errors and other human errors. When patents issue today, the paperwork is scanned using Optical Character Recognition (OCR). So instead of typographical errors, there are now computer errors in issued patents. In other words, the PTO’s process of converting the submitted document(s) to the formal issued patent often adds errors. Both applicant errors and PTO errors can be corrected using a Certificate of Correction, although there is an additional fee for correcting applicant errors.

Some errors can be found by a simple reading of the issued patent, and those errors can be corrected accordingly. Some errors, however, are more difficult to find. Proper proofreading includes, for example, (1) a comparison of the issued patent's front page information with the prosecution history (including confirmation of the title, confirmation of inventor information, confirmation of priority information, cross-verification of references, and verification of the abstract), (2) a visual verification of the drawings (e.g. drawings as originally submitted and/or any replacement drawings submitted during prosecution) to ensure that correct drawings appear in the issued patent, (3) a paragraph-by-paragraph comparison of the "specification as issued" and the "specification as filed," keeping in consideration amendments made during prosecution, and (4) a comparison of the issued patent claims with the "latest claim amendment filed" including the "latest Examiner's amendment." In other words, proofreading is the process of reviewing the issued patent as it compares to the original application and the file history (all the changes made during the patent prosecution history). Proper proofreading really requires two proofreaders, one to read out loud and one to follow along. While the proofreaders focus on finding PTO errors caused by the OCR process, they also try to find minor grammatical and typographical errors that may not have been found earlier during the preparation of the application and the process of obtaining the patent.

Mistakes that can be corrected using a Certificate of Correction include mistakes that are immediately apparent and leave no doubt as to what the mistake is based on (e.g. either the application itself or the prosecution history). Immediately apparent mistakes include, for example, misspellings, grammatical errors, typographical errors, clerical errors, printing errors, and other errors that leave no doubt as to what the correction should be. Correctable errors made by the applicant must have been made in good faith, may not introduce new matter, and may not require reexamination. Not all errors can be corrected using a Certificate of Correction.

Exemplary significant errors that have been found by my proofreaders include, but are not limited to, a changed word in the title, missing paragraphs, amendments not included in the claims (that should have been included), changes in mathematical formulas, incorrect figures associated with the patent, and more! Usually, however, the errors are much less significant (e.g. commas turned into periods, words that should be italicized not being italicized, and repeated words). If all the errors are minor and would be apparent to the reader, there may not be a necessity to request a Certificate of Correction.

Once the Certificate of Correction issues, it is considered part of the original patent. The patent, together with the Certificate of Correction, has the same effect and operation in law on the trial of actions for causes thereafter arising as if they had been originally issued in the corrected form.

If litigation is contemplated, the Certificate of Correction should be obtained prior to initiating the litigation. For some errors, the Certificate of Correction is valid only for causes of action arising after the issuance of the Certificate of Correction and, therefore, failure to file the Certificate of Correction may have a significant impact on the liability of infringers. In other words, if an error is significant, the accused infringer might present the argument that he did not infringe until he was able to determine his infringement based on the corrections, so his actions before the corrections should not be considered infringement. Group One Ltd. v. Hallmark Cards Inc., 74 U.S.P.Q.2d 1759 (Fed. Cir. 2005) provides an example of when the patent owner should have filed a Certificate of Correction before suing for infringement. Although it was the PTO’s printing error that caused the omission of key claim language in the patent, the patent owner did not correct the error. At trial, the district court could not correct the error since the error was not evident from the face of the patent. The patent was held invalid for indefiniteness.

The PTO provides a Certificate of Correction with issued patents. For example, patents found using the search facilities at http://www.uspto.gov/patft/index.html have Certificates of Correction that can be accessed using the "image" link and looking at the last page of the document. Further, the PTO publishes a list of Certificates of Correction in the Official Gazette, which you can find online at http://www.uspto.gov/web/patents/certofcorrect.