Chrysler Corporation and Robert W. Kearns appeal and cross-appeal, respectively, from the final judgment of the United States District Court for the Eastern District of Michigan awarding Kearns $18,740,465.43. The judgment was entered on jury verdicts that three patents owned by Kearns were infringed by Chrysler. Kearns v. Chrysler Corp., Civil No. 82-70748 (E.D.Mich. Oct. 30, 1992). The court denied Chrysler’s motion for judgment as a matter of law or in the alternative for a new trial. Kearns v. Chrysler Corp., Civil No. 82-70748 (E.D.Mich. June 3, 1993). We affirm the judgment in all respects.
BACKGROUND
In 1982, Kearns filed an action against Chrysler alleging infringement of U.S. Patents 3,351,836, 3,564,374, 3,602,790, and 3,581,178, all relating to electronic intermittent windshield wipers (IWWs) for use in automotive vehicles. At the time the suit was filed, Kearns had three similar suits pending against other automobile manufacturers and distributors involving the same patents, Kearns v. Ford Motor Co., Civil Action No. 78-70740 (E.D.Mich.); Kearns v. Wood Motors, Inc., Civil Action No. 78-70642 (E.D.Mich.); SWF-Spezialfabrik fur Autozubehor Gustav Rav GmbH v. Kearns, Civil Action No. 79-74451 (E.D.Mich.). 1
On October 22, 1982, proceedings in the Chrysler action were stayed pending resolution of the earlier filed suits. The stay was instituted pursuant to Chrysler’s stipulation that it would be “bound by the judgment as to the validity of ... U.S. patent Nos. 3,351,-836, 3,564,374, 3,581,178, and 3,602,790” in either Ford, Wood Motors, or SWF, whichever was the last to be adjudicated. The stipulation expressly provided, however, that Chrysler would “not be bound by any consent judgment.”
In 1989, shortly before the Ford case went to trial, Chrysler renewed its stipulation regarding the issues of invalidity and unen-forceability. Subject to continuation of the court-ordered stay, Chrysler agreed to be “bound by the judgment (excluding a consent judgment) in the Kearns v. Ford case, C.A. 78-70740 as to the validity and enforceability of the patents involved in that action that are also involved in this action. Those patents included United States Patent Nos. 3,351,836, 3,564,374, 3,581,178, and 3,602,790.” That stipulation was subsequently entered by the court on February 15, 1990.
1. The Ford Litigation
The liability phase of the Ford case commenced on January 3, 1990. On January 29, 1990, the jury returned a unanimous verdict for Kearns, finding that Ford had not proved by clear and convincing evidence that claim 16 of the ’836 patent, claim 6 of the ’374 patent, claim 14 of the ’790 patent, and claim 6 of the T78 patent were invalid or unenforceable. On March 9, 1990, the district court entered partial judgment that the specified claims were valid, enforceable, and infringed by Ford. That partial judgment was eventually “made final” upon entry of the court’s final judgment on November 14,1990.
*1544 The damage phase of Ford was tried before the same jury in April, 1990. The jury, however, was unable to reach a unanimous verdict and a second trial on damages was held in July, 1990. The second jury ultimately returned a unanimous verdict in favor of Kearns, awarding $5,163,842 for the period from April 3,1978 through 1988. On July 13, 1990, partial judgment was entered on the damage award assessed by the second jury. Although damages for the period from 1972 to April 3, 1978 remained in dispute, Ford and Kearns eventually reached a settlement as to the total amount of liability. Consequently, the partial judgment on damages was vacated and Ford withdrew its pending post-verdict motions for judgment notwithstanding the verdict or in the alternative for a new trial and waived its appellate rights.
2. The Chrysler Litigation
The Chrysler case returned to active status in early 1991. On February 20,1991, the district court issued a pretrial order stating that the issues to be adjudicated at trial concerned “infringement, damages, and willfulness.” On May 3, 1991, Chrysler filed a motion to have the pretrial order modified to add patent validity as an issue for trial. In support of its motion, Chrysler argued that the pretrial stipulations of October 15, 1982 and February 15, 1990 did not bar Chrysler from challenging the patents in suit. Chrysler claimed that because the final judgment in Ford was entered pursuant to a settlement agreement between Ford and Kearns, it was a “consent judgment” within the meaning of the stipulations.
The district court denied the motion and limited trial to the issues stated in the pretrial order. In rejecting Chrysler’s argument, the district court noted that although a settlement had been reached in Ford on the issue of damages, the issue of validity was “hotly” contested by the parties at trial, resulting in a unanimous jury verdict and a final judgment in favor of Kearns. Moreover, the court found that the stipulations did not obligate Ford to pursue post-trial motions and exhaust all rights of appeal in order for the judgment in Ford to be binding on the parties in Chrysler.
By order of the court, the Chrysler action was bifurcated into separate jury trials on the issues of liability and damages. On December 10, 1991, the jury returned verdicts that Chrysler’s accused IWW circuits, designated the “1977 Circuit” and the “1980 Circuit,” infringed claim 12 of the ’836 patent, claim 6 of the ’374 patent, and claim 14 of the ’790 patent. 2 On June 11,1992, the same jury returned a verdict that Chrysler’s infringement was not willful and assessed a reasonable royalty of $.90 per unit for a total of 12,564,107 infringing units. 3 Pursuant to the jury’s verdicts, the district court entered final judgment in favor of Kearns in the amount of $18,740,465.43, including prejudgment interest and costs. 4
Chrysler subsequently filed a motion for judgment as a matter of law (JMOL), asserting that the jury’s findings of infringement were not supported by substantial evidence. Alternatively, Chrysler moved for a new trial, claiming that the district court improperly excluded evidence and misinstructed the jury on critical legal issues. The district court denied Chrysler’s post-verdict motions. The court considered the expert testimony adduced at trial together with the documentary evidence of record to be a sufficient basis upon which the jury could have supported its findings of infringement. Further, the court determined that the exclusion of evidence *1545 was not prejudicial to Chrysler’s substantive rights and that the jury was correctly instructed on the interpretation of the claims and their application to the accused circuits.
DISCUSSION
Chrysler now appeals, asserting that the district court’s judgment should be reversed as a matter of law because the underlying jury verdicts of infringement were not supported by substantial evidence, or in the alternative, that a new trial is warranted in view of the prejudicial error committed by the district court in barring Chrysler from introducing prior art evidence necessary to properly construe the claims at issue and to challenge their validity and enforceability. Kearns cross-appeals certain rulings of the court that allegedly deprived him of the total compensation to which he claims he is entitled.
New Trial
We first address the district court’s denial of Chrysler’s motion for a new trial. “The denial of a motion for new trial can be reversed only if the district court abused its discretion.”
Arachnid, Inc. v. Medalistic Marketing Corp.,
1. Invalidity and Unenforceability
In support of its contention that a new trial is required, Chrysler claims that the district court erred as a matter of law in excluding evidence allegedly showing that the patents in suit are invalid and unenforceable. Chrysler claims that the district court’s decision to exclude such evidence was based on an erroneous interpretation of the pretrial stipulation of February 15, 1990, 5 in which Chrysler agreed to be bound by the judgment rendered in the Ford case on the issues of invalidity and unenforceability. It is Chrysler’s position that the Ford judgment was in fact a consent judgment, which, under the terms of the stipulation, was not binding on Chrysler.
The proper interpretation of the parties’ pretrial stipulation, like any contract, presents a legal question that we address
de novo. See Intel Corp. v. ULSI Sys. Technology, Inc.,
The controlling language of the agreement between Chrysler and Kearns provides that Chrysler “shall be bound by the [Ford] judgment (excluding a consent judgment) ... as to the validity and enforceability” of the patents in suit. [Emphasis added.] Chrysler asserts that the existence of the “consent judgment” exception in the stipulation indicates that it only intended to be bound by a judgment respecting invalidity and unenforceability where those issues were “fully litigated” by Ford, i.e., only after Ford vigorously defended its position at trial and exhausted all available post-trial remedies. Chrysler insists that the final judgment entered in Ford was a “consent judgment” because the parties in that case reached a settlement on the issue of damages that effectively mooted Ford’s post-trial motions and forced Ford to forfeit its appellate rights.
*1546
We reject Chrysler’s attempts to avoid the consequences of its stipulation by redefining its terms. The fact that Ford was precluded from proceeding with its post-trial motions or seeking appellate review because of its damage settlement does not render the court’s judgment a “consent judgment.” In our effort to give effect to the original intent of the parties, we adhere to the well-settled rule that words in an agreement are interpreted in accordance with their ordinary and commonly accepted meanings.
See Hol-Gar Mfg. Corp. v. United States,
Although it is undisputed that Ford settled the amount of compensation due Kearns, no such settlement or agreement was reached between the parties in Ford respecting the issues of validity, enforceability, and infringement of the asserted patent claims. Indeed, as the trial court noted, those issues were “hotly,” “vigorously,” and “fully” contested by the parties during a lengthy jury trial. 6 Pursuant to unanimous verdicts returned by the jury, the court entered partial (and later final) judgment holding claim 16 of the ’836 patent, claim 6 of the ’374 patent, claim 14 of the ’790 patent, and claim 3 of the ’936 patent valid, enforceable, and infringed. Because neither party in Ford “settled and agreed” on the issues of validity and enforceability, the district court’s judgment respecting those issues was not a “consent judgment” within the meaning of the stipulation. Chrysler is thus bound by that judgment. See Restatement (Second) of Judgments § 40 (1982) (“A person who agrees to be bound by the determination of issues in an action between others is bound in accordance with the terms of his agreement.”).
In a further attempt to avoid the consequences of its stipulation, Chrysler urges that “public policy” favors allowing it to challenge the patents’ validity and enforceability. Even were we to agree with this proposition, we do not see how it aids Chrysler here. Chrysler was certainly entitled to raise the defenses of invalidity and/or unenforceability when it was accused of infringement, but it chose instead to rely on the judgment rendered in
Ford
on those issues. Public policy will not rescue Chrysler from a decision which it later finds to be imprudently made. On the contrary, public policy favors preventing Chrysler from reneging on an agreement into which it freely entered and upon which Kearns and the district court relied.
See Interspiro USA Inc. v. Figgie Int’l Inc.,
Accordingly, we agree with the district court that Chrysler was barred under the stipulation from introducing prior art evidence directed toward challenging-the validity and enforceability of the asserted patents in this case.
2. Interpretation of Claims
Next, Chrysler contends that the district court committed reversible error by excluding prior art evidence allegedly essential to the px’oper construction of the claims at issue. As a result of that error, Chrysler asserts that a new trial is warranted because the jury’s infringement analysis was predicated on distorted claim interpretations.
*1547
“The decision to admit or exclude evidence is within the sound discretion of the trial court and will be reversed on appeal only for a clear abuse of that discretion.”
Smith & Lee
Assocs.,
Inc. v. City of Taylor, Mich.,
It is well-settled that reference may be had to prior art when it will assist a court in determining how a disputed claim is understood by those skilled in the art.
See Palumbo v. Don-Joy Co.,
Whether a claim has been infringed requires first interpreting the claim and then comparing the properly construed claim to the accused device.
See Read Corp. v. Portec, Inc.,
At trial, Chrysler attempted to introduce prior art patents ostensibly for the purpose of aiding in the interpretation of the claims at issue. Specifically, Chrysler intended to show that under Kearns’ interpretations of the claims, the claims were impermissibly broad because they read upon or were obvious over the prior art. The district court, however, concluded that the claims could be construed according to their plain meaning and that reference to prior art was not required. 7 Moreover, and highly significant here, the district court believed that Chrysler’s attempts to offer such evidence constituted a disguised, “back door” attack on the validity of the patents, which was expressly proscribed by the binding stipulation.
The district court’s reasoning adequately supports its refusal to admit the proffered evidence. “[That] we might have reached a different result or might have affirmed had the district court gone the other way are insufficient bases for reversal under the abuse of discretion standard which applies to our review of this part of the court’s judgment.”
RCA Corp. v. Data General Corp.,
Judgment as a Matter of Law
We now consider Chrysler’s argument that the district court erred in denying its motion for judgment as a matter of law on the issue of infringement. Chrysler contends that no substantial evidence supports the jury’s findings that Chrysler literally infringed claim 14 of the ’790 patent, claim 16 of the ’836 patent, and claim 6 of the ’374 patent.
“We reverse a denial of a motion for JMOL only if the jury’s factual findings, presumed or express, are not supported by substantial evidence or, if they are, that the legal conclusions implied from the jury’s verdict cannot in law be supported by those
*1548
findings.”
Arachnid, Inc. v. Medalistic Marketing Corp.,
Chrysler devotes the bulk of its appeal to challenging the jury’s findings that the accused circuits performed the functions required by each of the asserted means-plus-function clauses by means of structure taught in the specification or an equivalent of those structures. In doing so, Chrysler pays mere lip service to the substantial evidence standard by ignoring the evidence upon which the jury reasonably relied in reaching its verdicts and by rearguing the merits of the infringement issues. An appeal, however, is not to be used as a means of retrying a case.
See DMI,
Trial on the issue of infringement lasted approximately four weeks, during which expert testimony was introduced by both parties. Specifically, as the district court stated, “the expert testimony first construed each of the asserted claims and then went on to describe how the Chrysler system responded to each of the elements of each of the claims_ It is this expert testimony together with admissions in Chrysler’s documents describing the gestation of the Chrysler system which constituted, for the most part, the substantial evidence supporting the jury’s verdict of infringement.” After receiving instructions on the law governing infringement of means-plus-function claims, 8 the jury returned verdicts that the asserted claims were literally infringed by Chrysler’s accused IWW circuits. Each of the jury’s verdicts of infringement was supported by a number of detailed special interrogatories (referred to at trial as “special questions”) that addressed specific issues that had been the focus of expert testimony at trial. 9
We have recognized that “[t]he use of special interrogatories ... facilitates appellate review ... for such use frees the court from having to survey every possible basis for the jury’s decision.”
American Hoist & Derrick Co. v. Sowa & Sons, Inc.,
We conclude that Chrysler has failed to show that on the entirety of the record reasonable persons could not have found the facts necessary to support the jury’s verdicts of infringement. Because substantial evidence supports the jury’s verdicts and because the legal conclusions implied from those verdicts are consistent with the jury’s findings, the district court’s denial of Chrysler’s motion for judgment as a matter of law is affirmed.
Cross-Appeal
Kearns now cross-appeals a number of rulings issued by the district court that Kearns claims precluded him from obtaining all the relief and compensation to which he was entitled under the law. At issue are the district court’s orders (1) granting Chrysler’s motion for summary judgment on Kearns’ right to seek injunctive relief, (2) granting Chrysler’s motion for summary judgment on Kearns’ right to recover lost profits as damages, (3) denying Kearns’ motion to disqualify Chrysler’s counsel for conflict of interest, (4) precluding Kearns from challenging the number of infringing units without filing supporting documentary evidence, (5) denying Kearns’ motion to offer separate evidence of willful infringement by American Motors, (6) granting Chrysler’s motion for a directed verdict on the issue of willfulness, (7) assessing prejudgment interest for the period from March 2, 1982 to June 11, 1992 at simple interest rather than 2% above the prime rate, and (8) awarding Chrysler $677,332.62 for attorneys’ fees and expenses. We will address each of these rulings in turn to the extent necessary.
1. Post-expiration Injunctive Relief
Shortly before trial, Kearns expanded his claim for relief to include injunctive relief. Kearns believed that Chrysler’s infringement deprived him of the “full value” of his patents during their respective terms by effectively extinguishing his exclusive right to sell his patented IWW systems to automobile manufacturers. Kearns urged that Chrysler should be enjoined from manufacturing infringing IWW systems for a period of sufficient duration “to put him in [a] position where the harm [caused by] past infringement during the terms of the patents in suit is rectified.” The district court refused to grant such relief because the patents had already expired. 10 The court concluded that “there is nothing in statute or common law giving [Kearns] the right to an injunction against practicing the disclosures in an expired patent.”
In arguing that the district court erred in denying him post-expiration relief, Kearns claims that the $11 million damage award is not adequate to compensate him for the loss he sustained as a result of Chrysler’s infringement. Kearns contends that Chrysler’s infringement stripped him of “exclusive time” over his patents in violation of his rights under the U.S. Constitution and the patent laws, and that he is entitled to have that time restored to him. That contention, however, finds no basis in the statutory scheme governing patent infringement remedies.
Under the laws enacted by Congress, a patent grants the patent owner the right to exclude others from making, using, or selling the claimed invention in the United States for the term of seventeen years. 36 U.S.C. § 154 (1988). When that exclusive right is infringed, the patent owner is authorized to obtain compensation in the form of damages, measured,
e.g.,
by lost profits or a reasonable royalty. 35 U.S.C. §§ 281, 284 (1988). Moreover, the statute expressly provides for the grant of injunctions “in accordance with the principles of equity.” 35 U.S.C. § 283 (1988). In view of the fact that the principal right afforded by a patent is the “right to exclude,” we have noted that “[t]he nature of
*1550
the patent grant ... weighs against holding that monetary damages will always suffice to make the patentee whole.”
H.H. Robertson Co. v. United Steel Deck, Inc.,
An invention claimed in a patent passes into the public domain upon termination of the patent’s 17-year statutory term. Because the rights flowing from a patent exist only for the term of the patent, there can be no infringement once the patent expires. Here, all the asserted patents expired before the commencement of trial. Therefore, Kearns “can no longer obtain injunctive relief with respect to [those patents].”
See Kinzenbaw v. Deere & Co.,
Kearns argues that our decision in
Roche Prods., Inc. v. Bolar Pharmaceutical Co., Inc.,
The post-expiration relief discussed in Roche was intended to return the parties to the status quo before infringement (e.g., destruction of data obtained as a result of the infringement) and was not intended to prohibit future use of the invention. Importantly, the relief was also considered in the context of harm to a patent owner that had been selling the patented product. Thus, deferral of competition by an infringer who had entered the market prematurely, i.e., before the patent expired, was considered as a means of equitably compensating the patent owner. In contrast, because Chrysler has been manufacturing and selling its infringing IWWs for many years and Kearns has not (see infra), there is no basis for granting relief similar to that contemplated by the court in Roche.
We sympathize with Kearns’ complaint that his patents have expired without his ever being able to exclude others from prac
*1551
tice of his invention, especially since he is an individual inventor contending with a multitude of giant corporations.
11
While it is of course the essence of a patent that it provides the right to exclude, the same statute that grants that right also permits other parties, including accused infringers, to challenge the validity of a patent and to contest a charge
of
infringement.
See
35 U.S.C. § 282 (1988). Moreover, entitlement to an injunction implementing the right to exclude, as compared with only assessing damages against an infringer, is not absolute even during the life of a patent, but is discretionary.
See
35 U.S.C. § 283 (“courts having jurisdiction of cases under this title
may
grant injunctions” (emphasis added));
see also City of Milwaukee v. Activated Sludge, Inc.,
It is unfortunate that Kearns feels that he never enjoyed an exclusive status under his patents, but that is simply a consequence of the right of others to challenge his patents and the fact that his patents have expired. The patent statute does provide for increased damages and attorney fees as additional relief for aggrieved patent owners, see 35 U.S.C. §§ 284, 285 (1988), but Kearns did not persuade the district court that he was entitled to such relief.
We therefore conclude that the district court properly granted summary judgment in favor of Chrysler on Kearns’ request for post-expiration injunctive relief.
2. Lost Profits
Kearns argues that the district court erred in granting Chrysler’s motion for summary judgment on Kearns’ claim for damages based on lost profits, rather than a reasonable royalty. A patent owner bears the burden of proof on damages.
Fromson v. Western Litho Plate and Supply Co.,
A' lost profits award is appropriate only if the patent owner can prove there was a reasonable probability that “but for” the infringement, it would have made the infringer’s sales.
Water Technologies Corp. v. Calco, Ltd.,
In ruling against Kearns, the district court concluded that Kearns failed to prove the
Panduit
requirements for lost profits, particularly with regard to whether he possessed the capability to manufacture and market IWWs. The court determined that “[a]t best plaintiff’s offer of proof demonstrates plans for manufacture that were tentative, speculative and contingent. Plaintiff does not suggest he ever made any sales of intermittent windshield wipers or had the manufacturing capability in hand to do so.” Kearns disputes the court’s finding, stating that his company “Kearns Engineers” had the capacity to manufacture, market, and sell IWWs since the 1960’s and that Chrysler’s infringement prevented him from selling his IWWs to Chrysler. That contention, howev
*1552
er, is not supported by the record.
12
Where, as here, a patent owner fails to prove lost profits, the court is left with no alternative but to have damages determined on the basis of a reasonable royalty.
See Water Technologies,
Accordingly, we affirm the district court’s grant of summary judgment in favor of Chrysler on the issue of lost profits.
3. Other Rulings
We have carefully reviewed the district court’s other rulings respecting willful infringement, disqualification of counsel, prejudgment interest, and attorneys’ fees and costs. The rulings are adequately supported by the record and are consistent with governing law. We need not address Kearns’ contentions in detail. For purposes of our decision, suffice it to say that Kearns has not identified any reversible error in law or fact made ■ by the district court in reaching its decisions. Accordingly, we affirm the district court’s rulings.
CONCLUSION
The district court did not err in denying Chrysler’s post-verdict motions. Nor did the district court commit any reversible error in ruling on the various issues disputed by Kearns. Accordingly, the district court’s judgment is affirmed in all respects.
AFFIRMED.
Notes
. Keams subsequently filed other infringement actions involving patents relating to IWWs,
e.g., Kearns v. General Motors Corp.,
Civil Action No. 85-70461 (E.D.Mich.),
aff'd,
.The jury also found that Chrysler infringed claim 7 of the '178 patent. Due to an inconsistency between the jury's general verdict of infringement and its answer to a special question, the district court set aside the jury’s finding and entered judgment of noninfringement pursuant to Fed.R.Civ.P. 49(b). The court's judgment respecting claim 7 is not at issue in this appeal.
. The Court subsequently revised the number of infringing units downward to 12,563,107 units.
. Specifically, the judgment consisted of $11,-306,696.30 for infringement damages, $8,075,-193 for prejudgment interest, and $25,898.75 for costs, less $667,322.62 in costs, expenses, and attorneys' fees awarded to Chrysler.
. The district court did not rely on the first stipulation of October 15, 1982 in making its disputed evidentiary rulings. The court considered that stipulation to be functus officio in view of the February 15, 1990 stipulation. We will therefore limit our discussion to the latter stipulation.
. The judge who presided over the Ford litigation also presided over the Chrysler litigation. In rejecting Chrysler’s initial attempts to avoid its stipulation, Judge Cohn stated, "I know that I entered a Partial Judgment of Validity, after a hotly contested trial. To my way of thinking ... there was no Consent Judgment on Validity. Validity was contested. Kearns won, Ford lost and it chose not to appeal, and it withdrew its Motions JNOV or New Trial. That doesn't obviate the fact that it was judgment contested arising in a contested environment.”
. The claims at issue contain limitations expressed in ''means-plus-function” format. 35
U.S.C.
§ 112 ¶6 (1988). The court’s ruling is consistent with the rule that ”[i]t is not necessary to consider the prior art in applying section 112, paragraph 6. Even if the prior art discloses the same or an equivalent structure, the claim will not be limited in scope thereby.”
Intel Corp. v. United States Int'l Trade Comm’n,
. "In order to meet a means-plus-function limitation, an accused device must (1) perform the identical function recited in the means limitation and (2) perform that function using the structure disclosed in the specification or an equivalent structure.”
Carroll Touch, Inc. v. Electro Mechanical Sys., Inc.,
. The jury decided some 39 special questions concerning the issue of infringement. Five special questions were directed to infringement of claim 5 of '790 patent, 17 special questions to claim 16 of the '836 patent, and five special questions to claim 6 of the '374 patent.
. The '836 patent expired in 1984 and the '790 and '374 patents both expired in 1988.
. The fact that Kearns has fired several of his attorneys and attempted to conduct massive multiple suits pro se may be relevant to his dilemma,
. We note that the appendices filed by Kearns on appeal contain documents not considered by the district court. We, of course, must limit our review to the record produced at trial.
DMI,