First published in LES Insights

Abstract

The Federal Circuit recently found that certain patent claims reissued by the U.S. Patent and Trademark Office were invalid in view of the Court's earlier claim construction of the patent's original claims. The patent owner argued that the successful prosecution of the reissued patent claims served as new evidentiary proof that the Federal Circuit's earlier construction of a claim limitation was wrong. However, the Federal Circuit held that the reissued claims could not be used to redefine the scope of the earlier-adjudicated original claims.

Under the United States patent law, a patent owner may seek to enlarge the scope of issued patent claims using a reissue proceeding only if the reissue is applied for within two years from the grant of the original patent. Thus, if a reissue application is filed more than two years after grant of the original patent, any reissued claims that are found to have broadened the scope of the original claims will be held invalid. A comparison, therefore, of the scope of the original claims to that of the reissued claims is paramount.

In a recent case, ArcelorMittal France v. AK Steel Corp.,1 an interesting issue arose where, more than two years after an original patent grant, ArcelorMittal applied for and obtained reissued claims from the United States Patent and Trademark Office (USPTO) based on an original patent, which had already been construed by a district court in a prior litigation proceeding. In fact, the Federal Circuit had affirmed the district court's construction. Although original claim 1 and reissued claim 1 were identical, a dependent claim added by ArcelorMittal during reissue broadened the scope of a particular limitation in claim 1 compared to that limitation's scope as earlier affirmed by the Federal Circuit. The patent owner argued that the successful prosecution of the reissued patent claims served as new evidentiary proof that the Federal Circuit's earlier construction of the limitation was wrong, such that the reissued claims did not broaden those that originally issued. Rejecting this argument, the Federal Circuit held that the reissued claims could not be used to redefine the scope of the earlier-adjudicated original claims.

Background

ArcelorMittal sued AK Steel Corporation and two other companies for infringement of its U.S. Patent No. 6,296,805 (the '805 patent) directed toward a specific type of steel sheet that has "a very high mechanical resistance" after thermal treatment. The Delaware district court construed the phrase "a very high mechanical resistance" as limited to steel with a tensile strength greater than 1500 MPa. At trial, the jury found the patent not infringed and invalid as anticipated and obvious. ArcelorMittal appealed. The Federal Circuit affirmed the district court's claim construction, while reversing and remanding the case on other grounds.

In conjunction with its first appeal and well over two years after the '805 patent issued, ArcelorMittal applied for, prosecuted, and was subsequently granted Reissue Patent No. RE44,153, in which it added a number of dependent claims. New dependent claim 23 recited "[t]he coated steel sheet of claim 1, wherein said mechanical resistance is in excess of 1000 MPa," which was outside the scope of the greater-than-1500 MPa construction earlier affirmed by the Federal Circuit during the '805 patent litigation. Thus, reissued claim 23 and independent claim 1—from which claim 23 depended—were broader in scope than the earlier-adjudicated construction. New dependent claim 24 recited "[t]he coated steel sheet of claim 1, wherein said mechanical resistance is in excess of 1500 MPa," consistent with the prior claim construction.

On remand after its first appeal, ArcelorMittal amended its complaint to substitute the now-surrendered '805 patent for the reissued claims. AK Steel moved for summary judgment of invalidity against the reissued claims, arguing that ArcelorMittal improperly broadened the scope of the original '805 patent claims. The district court granted AK Steel's motion, and ArcelorMittal again appealed.

The Federal Circuit's Decision

The pertinent question on appeal was whether the successful prosecution of ArcelorMittal's reissued patent claims at the USPTO redefined the scope of the originally-construed claims, such that the reissued claims did not enlarge the scope of the "mechanical resistance" limitation. The Federal Circuit answered no.

Affirming that claims 1 through 23 were impermissibly broadened compared to the '805 patent's original claims, the Federal Circuit invoked the "law-of-the-case doctrine," which provides that once a court decides upon a rule of law, that decision will subsequently govern the same issues in the same case. According to the Court, the doctrine prohibited the district court from revisiting the prior construction of "a very high mechanical resistance." In addition, under the "mandate rule," the Federal Circuit noted that the district court lacked authority to deviate from the appellate Court's earlier construction of that limitation.

ArcelorMittal argued that the successful prosecution of the reissue patent was "new evidence" of extraordinary circumstance sufficient to deviate from the doctrines above. But the Court rejected that argument, concluding that the comparison of original claims to reissued claims would be rendered "meaningless" if the reissued claims could redefine the scope of the original claims. The dispositive question, the Court emphasized, was "whether the original claim ha[d] the meaning sought by ArcelorMittal for the reissue claims—not what the original claim mean[t] in light of the reissue claims." Because the Federal Circuit had already construed the original claims, and reissued claims 1 through 23 were broader than that construction, the Court affirmed summary judgment of invalidity.

On the other hand, the Court found error in the district court's judgment invalidating reissued claims 24 and 25 on the basis of improper broadening. According to the Court, the district court should have conducted a claim-by-claim analysis with respect to improper broadening. Claims 24 and 25 provided that the mechanical resistance "is in excess of 1500 MPa," (i.e., the same scope as the prior construction). Thus, the Federal Circuit reversed the district court's judgment of invalidity of those claims.

Strategy and Conclusion

This decision shows that patent owners cannot use a reissue proceeding to redefine the scope of original claims after an unfavorable claim construction, but may want to consider whether to apply for and obtain reissued patent claims before risking an unfavorable claim construction in an infringement suit.