## Facts

- Ball owned U.S. Reissue Patent No. Re. 29,296 covering a dual slot antenna assembly for missiles.
- In the original prosecution, claims covering “at least one” conductive lead (feedline) were canceled to overcome prior art, and the issued patent claimed only “a plurality” of conductive leads.
- Within two years, Ball sought reissue under 35 U.S.C. § 251, asserting the “plurality” limitation was an error made without deceptive intent that left the patent partially inoperative by excluding intended single-feedline embodiments.
- The reissue issued with additional claims (claims 5–7) directed to a single-feedline configuration, while retaining multiple-feedline claims.
- Ball alleged the United States used antennas within reissue claims 5–7 without authorization and sued for compensation under 28 U.S.C. § 1498(a).
- The government moved for summary judgment that the reissue claims were invalid under the recapture rule and estoppel theories; the trial court denied summary judgment and certified an interlocutory appeal.

## Issues

1. Whether reissue claims covering a single feedline were invalid under the reissue “recapture rule” because similar subject matter had been canceled during original prosecution to obtain allowance.
2. Whether prosecution history or equitable estoppel independently barred Ball from obtaining or asserting the reissue claims.
3. Whether Ball satisfied 35 U.S.C. § 251 by showing an “error without deceptive intention” that made the original patent partially inoperative for claiming less than it had a right to claim.

## Decision

- The Federal Circuit affirmed the denial of the government’s motion for summary judgment and remanded for trial.
- The court held the recapture rule did not bar reissue claims 5–7 because, although broader than the original issued “plurality” claims, they were narrower than the canceled “at least one lead” claim and included additional limitations.
- The court held the § 251 reissue “error” requirement was satisfied on the presented record, reflecting a good-faith mistake that resulted in under-claiming without deceptive intent.
- The court rejected summary judgment based on a separate estoppel theory, reasoning that recapture addresses the relevant equitable concerns and the government did not establish an estoppel bar as a matter of law.
- The merits issues of government use/infringement and compensation under § 1498(a) remained for trial.

## Legal Principles

- The reissue recapture rule prevents a patentee from regaining, through reissue, subject matter surrendered to obtain allowance of original claims, but it is applied by comparing the scope and limitations of the canceled claims and the reissue claims.
- Reissue claims that are broader than the original issued claims may still be permissible if they are narrower than the surrendered subject matter and materially limited by additional claim restrictions.
- A reissue under 35 U.S.C. § 251 requires a showing that the original patent was inoperative or invalid “through error without any deceptive intention,” including under-claiming (claiming less than the patentee had a right to claim).
- Estoppel theories based on prosecution conduct do not automatically bar reissue; the applicability depends on the scope comparison and whether the asserted bar is established as a matter of law on the record.

## Conclusion

The Federal Circuit upheld interlocutory denial of summary judgment because the reissue claims to a single-feedline antenna were not an impermissible recapture of surrendered subject matter, met § 251’s error requirement without deceptive intent, and were not barred by estoppel as a matter of law, leaving liability and compensation to be resolved at trial.


Ball Corp. v. United States, 729 F.2d 1429 (Fed. Cir. 1984)