res judicata of the patent enforceability issue. We find it unnecessary to decide that question, however, because we conclude that the provision of the settlement Order requiring REI to make the payments without regard to any subsequent determination of the validity or enforceability of the patent bars the relief REI now seeks.
A. Under the settlement, “REI agree[d] to make said payments as they become due notwithstanding that said patents-in-suit may be held invalid and/or unenforceable in any other proceeding at a later date[.]” The possibility REI contemplated has come to pass. The patents were held unenforceable in “[anjother proceeding at a later date.” REI committed itself to make the payments even if that happened. Now that the event has happened, REI seeks to escape its commitment. It cannot do so.
The law strongly favors settlement of litigation, and there is a compelling public interest and policy in upholding and enforcing settlement agreements voluntarily entered into. Bergh v. Department of Transp., 794 F.2d 1575, 1577 (Fed.Cir.), Cert. denied, — U.S. —, 107 S.Ct. 437, 93 L.Ed.2d 386 (1986). REI makes no claim that this settlement was involuntary or tainted by fraud. Asberry v. United States Postal Service, 692 F.2d 1378, 1380 (Fed.Cir. 1982) (“ ‘One who attacks a settlement must bear the burden of showing that the contract he has made is tainted with invalidity, either by fraud practiced upon him or by a mutual mistake under which both parties acted.’ ”) (quoting Callen v. Pennsylvania R.R. Co., 332 U.S. 625, 630, 68 S.Ct. 296, 298, 92 L.Ed. 242 (1948)). The settlement presumably reflected REI’s judgment, made after the case had been on trial for a week, that REI’s interest would best be served by settling the case upon the terms to which it agreed (including its agreement to make the payments even if the patents subsequently were held invalid dr unenforceable), rather than to continue the trial to the jury verdict.
For almost six years after the settlement, REI made the payments it had agreed to make. It now seeks to avoid its obligation on the sole ground that, because in a subsequent case the patents were held unenforceable, it should not be required to pay for rights under unenforceable patents. Having specifically voluntarily agreed to make the payments even if the patents subsequently were held unenforceable, it ill behooves REI to renege on that commitment merely because the situation it contemplated has occurred. To permit REI thus to escape its obligation under the settlement would seriously decrease the willingness of parties to settle litigation on mutually agreeable terms and thus weaken the efficacy of settlements generally.
See Aro Corp. v. Allied Witan Co., 531 F.2d 1368, 1372, 190 USPQ 392, 395 (6th Cir.) (Markey,
C.J.), cert. denied, 429 U.S. 862, 97 S.Ct. 165, 50 L.Ed.2d 140 (1976) (“Settlement is of particular value in patent litigation, the nature of which is often inordinately complex and time consuming. Settlement agreements should therefore be upheld whenever equitable and policy considerations so permit.”).
B. REI points to Lear, Inc. v. Adkins, 395 U.S. 653, 89 S.Ct. 1902, 23 L.Ed.2d 610 (1969), in which the Supreme Court held that a patent licensee could challenge the validity of the licensed patent. The Court stressed “the important public interest in permitting full and free competition in the use of ideas which are in reality a part of the public domain.” 395 U.S. at 670, 89 S.Ct. at 1911. The Court also held that the licensee was not required to continue to pay royalties under the license while it was challenging the validity of the patent, because “such a requirement would be inconsistent with the aims of federal patent policy.” 395 U.S. at 673, 89 S.Ct. at 1912. REI contends that it also would be inconsistent with federal patent policy to require it to continue to pay royalties for a license under a patent that has been held unenforceable.
Lear, however, did not involve a settlement of litigation, but only the right of a patent licensee to challenge the validity of the licensed patent. The enforcement of settlement of litigation involves another public policy totally absent in Lear: the encouragement of settlement of litigation and the need to enforce such settlements in order to encourage the parties to enter into them.