## Facts

- A patent covering a safety trocar for endoscopic surgery (U.S. Patent No. 4,535,773) issued naming Dr. InBae Yoon as inventor; Ethicon held an exclusive license.
- Ethicon and Yoon sued United States Surgical Corp. for patent infringement in the District of Connecticut.
- Young Jae Choi intervened, alleging he was an omitted co-inventor and that he had granted United States Surgical a retroactive license under the patent.
- After trial, the district court found Choi proved co-inventorship of claims 33 and 47 and ordered correction of inventorship under 35 U.S.C. § 256.
- Following correction, the district court dismissed the infringement action because Choi, as a co-owner, had licensed United States Surgical and did not consent to the suit.

## Issues

1. Whether Choi proved by clear and convincing evidence, with corroboration, that he was a joint inventor of claims 33 and 47 under 35 U.S.C. § 256.
2. Whether a joint inventor who contributed to fewer than all claims becomes a co-owner of the entire patent, and whether Choi’s license could extend to the full patent and to past acts.
3. Whether an infringement action may proceed without all patent co-owners joining or consenting as plaintiffs.

## Decision

- The Federal Circuit affirmed the judgment.
- The court upheld the § 256 correction adding Choi as a co-inventor of claims 33 and 47, finding sufficient corroborated evidence and no clear error in the district court’s credibility determinations.
- The court held that joint inventorship as to any claim confers an undivided ownership interest in the entire patent.
- The court held that Choi’s license to United States Surgical, as written, granted broad rights commensurate with his undivided interest and could be made retroactive by agreement.
- The court affirmed dismissal because all co-owners must ordinarily join or consent to an infringement suit, and Choi’s refusal to join (coupled with his license to the accused infringer) barred the action.

## Legal Principles

- Correction of inventorship under 35 U.S.C. § 256 requires clear and convincing proof, and an alleged co-inventor’s testimony must be corroborated by independent evidence.
- Joint inventors need not contribute equally or to every claim; contribution to the conception of at least one claim is sufficient for joint inventorship.
- A joint inventor is a co-owner of the entire patent with an undivided interest, not a claim-by-claim or embodiment-limited interest, absent a contrary agreement among owners.
- A patent co-owner may license its undivided interest without the other co-owners’ consent; the license’s scope is governed by its terms and may be structured to apply retroactively between the contracting parties.
- As a general rule, all patent co-owners must join or consent as plaintiffs in an infringement action; any co-owner may withhold consent, preventing suit.

## Conclusion

The Federal Circuit affirmed correction of inventorship to add an omitted joint inventor, held that joint inventorship of even a single claim makes the inventor a co-owner of the entire patent, and ruled that a nonconsenting co-owner’s broad (including retroactive) license to the accused infringer and refusal to join required dismissal of the infringement suit.


Ethicon, Inc. v. United States Surgical Corp., 135 F.3d 1456 (Fed. Cir. 1998)