## Facts

- Sanders owned two reissue patents covering early video game display and interaction technology: U.S. Patent Re 28,507 and U.S. Patent Re 32,305 (reissue of U.S. Patent No. 3,829,095).
- Sanders granted Magnavox an exclusive license with sublicensing rights under the patents.
- Nintendo sued for declaratory relief seeking findings of invalidity, noninfringement, and unenforceability based on alleged inequitable conduct before the PTO; Magnavox and Sanders counterclaimed for infringement.
- The court bifurcated the case and tried only the threshold issue of inequitable conduct.
- Nintendo alleged misconduct including: nondisclosure of the “Space War” game and other prior art; inadequate investigation into prior art; an improper off-the-record examiner meeting (’507); failure to disclose issuance/status of a related patent and misleading communications (’507); and nondisclosure of the Glaser patent allegedly material to “light gun” claims (’095/’305).
- Nintendo’s core theory focused on attorney James T. Williams, who had seen Space War about 11 years before prosecution, remembered it only generally, discussed his recollection with co-counsel, and concluded in good faith it was not material enough to cite.

## Issues

1. Whether the ’507 and ’305 patents were unenforceable for inequitable conduct based on alleged nondisclosure, misrepresentation, inadequate investigation, and improper examiner contact during prosecution.
2. Whether failure to disclose Space War—given counsel’s partial recollection—satisfied the required showing of materiality and specific intent to mislead or deceive the PTO.

## Decision

- The court held Nintendo failed to prove inequitable conduct and refused to declare either patent unenforceable.
- As to Space War, the court found no clear and convincing evidence that counsel had detailed knowledge of material features and intentionally withheld it; the decision not to cite was a reasonable, if imperfect, judgment.
- The court found the remaining alleged episodes (ex parte contact, related-patent status, Glaser and other art, and alleged investigative deficiencies) showed, at most, carelessness and did not establish deceptive intent.
- The ruling resolved only the inequitable-conduct phase; validity and infringement issues remained for later proceedings.

## Legal Principles

- Inequitable conduct is an equitable defense that can render an entire patent unenforceable and therefore requires cautious application.
- The accused conduct must involve (1) material information (or misrepresentation) and (2) a separate, clear and convincing showing of specific intent to mislead or deceive the PTO.
- Negligence, poor judgment, administrative oversight, or imperfect investigation—without persuasive proof of intent—does not constitute inequitable conduct.
- Procedural irregularities (including off-the-record contacts) do not establish inequitable conduct absent proof they were used to mislead the examiner or suppress material information.

## Conclusion

The court declined to impose patent unenforceability because Nintendo did not prove, by clear and convincing evidence, that the applicants or their counsel acted with specific intent to deceive the PTO, even where materiality of certain prior art was disputed.


Nintendo of Am., Inc. v. Magnavox Co., 707 F. Supp. 717 (S.D.N.Y. 1989)