Addressing an attempt by a patent owner to assert a patent claim that was missing a material limitation, the U.S. Court of Appeals for the Federal Circuit affirmed a summary judgment of invalidity, finding that the patentee cannot assert the claim unless the omission is evident on the face of the patent. H-W Tech., L.C. v. Overstock.com, Inc., Case Nos. 14-1054, -1055 (Fed. Cir., July 11, 2014) (Prost, C.J.).

H-W Technology sued Overstock alleging infringement of its patent.  At the time of filing the complaint, H-W asserted the original version of the patent as issued, unaware that the asserted claim was missing a material limitation.  During the ensuing litigation, Overstock informed H-W of the missing limitation. H-W then sought to have the Patent and Trademark Office (PTO) issue a certificate of correction.  By the time the certificate issued, however, Overstock had already filed a motion for summary judgment on invalidity.  The district court disregarded the certificate of correction and determined that the asserted claim was invalid for indefiniteness.  H-W appealed.

Both H-W and Overstock agreed that the asserted claim was missing a limitation. As shown by the prosecution history, when the PTO allowed the claim it included the limitation in issue.  However, when the PTO issued the patent, the limitation was missing. The Federal Circuit found that H-W could not assert the claim with the missing limitation and rejected the three bases H-W asserted for saving it.

H-W argued that the district court itself should have corrected the claim, regardless of whether the PTO had issued a certificate of correction. The Federal Circuit, however, determined that the district court was correct to refuse to correct the claim because a district court can only correct a claim if “the error is evident from the face of the patent.” Here, when read in the context of the other claims, the asserted claim was coherent without the missing limitation. The omission was only evident upon reading the prosecution history, not from the face of the patent.  Therefore, the district court had no authority to correct the claim.

H-W also contended that the district court should not have ruled on Overstock’s summary-judgment motion without taking the certificate of correction into account.  The Federal Circuit disagreed. Under the plain language of 35 U.S.C. § 254, certificates of correction are only effective for causes of action arising after the certificate’s issuance.  In other words, any alleged infringement must occur after the PTO issues the certificate of correction.  Here, because the district court was ruling on a motion filed before the certificate of correction issued, the certificate of correction was irrelevant.

Finally, the Federal Circuit determined that the patentee could not assert the uncorrected version of the claim.  A patent owner cannot assert a patent claim when the claim “omits a material limitation” that is “not evident on the face of the patent.”  To allow a patent owner to assert a patent with a missing limitation would be to allow the patent owner to assert a patent that the patentee “never asked for nor rightly attained.” The public cannot be on notice of limitations that do not appear on the face of the patent.