Locating Re-examination Certificates

Patent attorney Stephen Nipper recently posted on his blog, The Invent Blog, a question about re-examination numbers. It seems that the USPTO website has some erroneous examples of re-examination document numbers.

In brief, anyone may file a request for a rexamination of a patent on the basis of prior art consisting of patents or other publications. The USPTO will examine the prior art and decided whether some, all or none of the claims of the patent in question should stand. At the end of the review the USPTO issues a re-examination certificate that sets forth the results of re-examination. This certificate is then attached to the original patent.

Re-examination certificates are not indexed in the USPTO's web-based patent database. Instead, users can retrieve a copy of the certificate by retrieving the original patent, e.g. by searching the patent number and clicking on the "Images" button to see the TIFF image. The re-exam certificate is attached after the claims section. (See 3,876,375.)