A valid reissue patent must satisfy 35 U.S.C. § 251, which requires that there be an “error” in the original patent.  On December 24, 2014, the Federal Circuit clarified this “error” requirement with its decision in Fleming v. Escort Inc., 2014 U.S. App. LEXIS 24419 (Fed. Cir. 2014).

In Fleming, the patentee alleged that he made an error when drafting his original patent because he did not “appreciate the full scope of his invention and the inadequacy of the original claims for properly capturing the full scope.”  Id. at *18-19.  The court called this a “classic reason that qualifies as error,” and found the reissue patent valid.  Id. at *19.

The court began its analysis by noting that “errors are not limited to slips of the pen but encompass … deliberate drafting choices.”  Id. at *18. The court stated, however, that there are limits to the error requirement, and that errors in the drafting choices must come from “deficient understanding of some combination of fact and law bearing on the meaning of claim language, the inventions disclosed in the written description, and how particular language does or does not map onto products or processes that could be claimed under § 251 consistent with the written description.”  Id. at *19.  There is no error if the drafting choice “rested on ‘no cognizable false or deficient understanding of fact or law,’” and was nothing but a “now-regretted choice.”  Id. at *18.

Escort, the defendant, argued that there was not error consistent with § 251 for two reasons.  First, Escort argued that because Fleming’s asserted error was the result of his perspective as a programmer it was not an error under § 251.  The court dismissed this argument because the patentee’s perspective as a programmer actually helps to explain the origin of the error, and does not undermine the premise that there was an error initially.  Id. at *19.  Second, Escort argued that the patentee’s asserted error was not an error under § 251 because he only reassessed his issued claims as a result of marketplace developments, indicating that the drafter simply made a “now-regretted choice.”  The court found this to be inconsequential, holding, “[e]rroneous understandings of the written description or claims are just that, regardless of what triggered the recognition of error in those understandings.”  Id.

This case displays the low bar that must be met for a court to find an error justifying reissue if the patentee shows that they had a deficient understanding of the facts or law when prosecuting the original patent.  It is important to note, however, that if the patentee cannot show such deficiency, a reissue patent will likely be found invalid. See In re Dinsmore, 757 F.3d 1343 (Fed. Cir. 2014).