dissenting.
This appeal is from a jury verdict of infringement, yet it is difficult to find in the majority opinion any deference to the jury, or application of the standard by which jury verdicts are reviewed on appeal. Thus I respectfully dissent from the review process followed by the panel majority. Applying the correct standard of review, I would affirm the judgment.
It is no more appropriate for the appellate court, than for the trial court on motion for judgment n.o.v., to decide the issue of infringement independent of the jury verdict. Tennant v. Peoria & P.U. Ry. Co., 321 U.S. 29, 33, 64 S.Ct. 409, 411, 88 L.Ed. 520 (1944) (when the issues have been properly presented to the jury, “[n]o court is then justified in substituting its conclusions for those of the twelve jurors”); Verdegaal Bros., Inc. v. Union Oil Co. of California, 814 F.2d 628, 631, 2 USPQ2d 1051, 1052 (Fed.Cir.), cert. denied, 484 U.S. 827, 108 S.Ct. 95, 98 L.Ed.2d 56 (1987) (“A trial court’s denial of a motion for JNOV must stand unless the evidence is of such quality and weight that reasonable and fair-minded persons in the exercise of impartial judgment could not reasonably return the jury’s verdict”.)
This court has emphasized that infringe-!' ment is a question of fact. Orthokinetics, Inc. v. Safety Travel Chairs, Inc., 806 F.2d 1565, 1578, 1 USPQ2d 1081, 1090 (Fed.Cir.1986) (appellate review determines if substantial evidence supported jury finding! that infringement had been proved by a preponderance of the evidence); Shatterproof Glass Corp. v. Libbey-Owens Ford Co., 758 F.2d 613, 626, 225 USPQ 634, 642 (Fed.Cir.), cert. dismissed, 474 U.S. 976, *822106 S.Ct. 340, 88 L.Ed.2d 326 (1985) (infringement and equivalence are questions of fact). A jury verdict on the question of infringement receives the classical deference due to jury verdicts. This deference is not diminished when a term in a patent claim is construed as a first step in the infringement analysis.
When the meaning of a term in a patent claim is in dispute, a jury may resolve the dispute. Palumbo v. Don-Joy Co., 762 F.2d 969, 974, 226 USPQ 5, 8 (Fed.Cir.1985):
If the language of a claim is not disputed, then the scope of the claim may be construed as a matter of law. But when the meaning of a term in the claim is disputed and extrinsic evidence is necessary to explain that term, then an underlying factual question arises, and construction of the claim should be left to the trier or jury under appropriate instruction. [Citation omitted]
The review process was described in Vieau v. Japax, Inc., 823 F.2d 1510, 1515, 3 USPQ2d 1094, 1098 (Fed.Cir.1987), wherein the court stated that the appellant’s burden “is to show that the jury’s factual findings were supported by at least substantial evidence and the legal conclusions made by the jury can be supported by those findings.” McGill Inc. v. John Zink Co., 736 F.2d 666, 672, 221 USPQ 944, 948 (Fed.Cir.) cert. denied, 469 U.S. 1037, 105 S.Ct. 514, 83 L.Ed.2d 404 (1984):
Since the jury did not make express findings on claim construction, we must presume the existence of facts necessary to support the claim construction urged by McGill and determine if those facts were supported by substantial evidence. Railroad Dynamics, supra. Zink must convince us that there is no set of facts, consistent with McGill’s interpretation, that was supported by substantial evidence.
In Railroad Dynamics, Inc. v. A. Stucki Co., 727 F.2d 1506, 1512, 220 USPQ 929, 936 (Fed.Cir.), cert. denied, 469 U.S. 871, 105 S.Ct. 220, 83 L.Ed.2d 150 (1984), this court stated that
the appellant must come prepared to show that the jury’s factual findings were not supported by substantial evidence, or if they were, that the jury’s legal conclusion was not supported by those facts.
Thus when it is necessary for the jury to interpret a claim en route to deciding the issue of infringement, the appellant
must demonstrate that no reasonable juror could have interpreted the claim in the fashion that supports the infringement finding.
McGill Inc., 736 F.2d at 672, 221 USPQ at 948.
It was not error to charge the jury with determining the meaning of words in the claims as a first step in its determination of whether the claims were infringed. The jury’s authority to decide questions of law as part of its fact-finding responsibility was affirmed early in the nation’s history. Often quoted is the jury charge by Chief Justice John Jay in Georgia v. Brailsford, 3 U.S. (3 Dali.) 1, 4, 1 L.Ed. 483 (1794):
But it must be observed that by the same law which recognizes this reasonable distribution of jurisdiction, you have nevertheless a right to take upon yourselves to judge of both, and to determine the law as well as the fact in controversy. On this, and on every other occasion, however, we have no doubt you will pay that respect which is due to the opinion of the court; for, as on the one hand it is presumed that juries are the best judges of facts, it is, on the other hand, presumable that the court are the best judges of law. But still both objects are lawfully within your power of decision.
The vitality of this decision-making process, and its consequence for appellate review of the jury verdict, has been analyzed and reaffirmed time and again by scholars of jurisprudence. See, e.g., M.B. Louis, Allocating Adjudicative Decision Making Authority Between The Trial and Appellate Levels: A Unified View of the Scope of Review, The Judge/Jury Question, and Procedural Discretion, 64 N.C.L.Rev. 993, 1003 (1986) (footnotes omitted):
*823Ultimate facts going to the merits are usually reviewed narrowly and deferentially like questions of historical fact even when the underlying historical facts are not in dispute. Indeed, with the exception of a few specific substantive areas like constitutional and contract or commercial law, mixed questions going to the merits are almost presumptively classified as questions of fact, assigned to the jury, and reviewed narrowly on appeal from any fact finder.
See also 5A Moore’s Federal Practice ¶ 50.07[2] at 50-70 (1988) (the reviewing court “must view the evidence in the light and with all reasonable inferences most favorable to the party who secured the jury verdict.”)
Many patent infringement determinations do not require a preliminary “claim interpretation”, an issue born of the imprecision of language. But when the meaning of words in claims is at issue, recourse is had to evidence to show what was intended when the claim was placed in the specification and allowed by the patent examiner. Pertinent evidentiary material is thus the patent specification and the prosecution history, and may extend to the prior art and other claims. Witnesses may testify as to how a person in the field of the invention would have viewed the questioned words. Tandon Corp. v. United States Int’l Trade Comm’n, 831 F.2d 1017, 1021, 4 USPQ2d 1283, 1286 (Fed.Cir.1987) (“When the meaning of key terms of claims is disputed, as in this case, extrinsic evidence may be adduced including testimony of witnesses, and reference may be had to the specification, the prosecution history, prior art, and other claims”); Moeller v. Ionetics, Inc., 794 F.2d 653, 657, 229 USPQ 992, 994 (Fed.Cir.1986) (resort to extrinsic evidence is always necessary to interpret disputed claims).
There was an issue in this case as to whether the word “on” in the claim phrase “on said anvil surface” meant that the staple touched the surface, or included a position of the staple above the surface without touching. The issue was pertinent to determination of literal infringement, for it was undisputed that in the accused device the staple did not touch the surface. And if the jury found that there was no literal infringement because in its view the claim required touching, the interpretation of the word “on” would still be predicate to application of the structure/function/result test of the doctrine of equivalents. However, the charge to the jury to interpret the claims does not transform the factual question of infringement into a question of law, or remove decisional authority from the jury. See generally Louis, supra at 1002-04 (discussing jury verdicts and appellate review).
The jury was instructed on the correct approach to deciding the question of infringement:
The first step in determining infringement is to construe the claims. The terms used in Becht 844 Patent Claims 1 and 2 must be interpreted as they would be by those of ordinary skill in the art. In understanding the meaning of the words used in the claims, you should consider: (1) the patent specification, (2) the prosecution history of the patent in the Patent Office, and (3) testimony of expert witnesses.
... if an inventor wishes to use a term in some particular way other than that understood by one of ordinary skill in the art at the time the application was filed, he must define it in his patent prior to the time it issues.
No challenge has been raised to the correctness of the jury instructions. Thus we review the jury verdict to determine whether there is any basis on which a reasonable jury could have reached the verdict reached by this jury. McGill, supra; Railroad Dynamics, supra. See generally 1 S. Childress and M. Davis, Standards of Review, p. 194 (1986):
That application of law to facts is the jury’s job, and on appeal it is generally not questioned in the same way that a judge’s findings on a bench trial appeal, under Federal Rule of Civil Procedure 52(a), might be called mixed law-fact and then split into the component parts, with the law part going more freely to the reviewing court. In this way the law-*824fact issue in jury trials is more a process than a rude dichotomy. [Emphasis in original]
In the process some issues called mixed law-fact in bench trials — and often reviewed more freely there — are unquestionably submitted to the jury. [Footnote omitted]
S. Weiner, The Civil Jury Trial and the Law-Fact Distinction, 54 Calif.L.Rev. 1867, 1919 (1966):
As a working rule, the task of law application should be entrusted to the jury, unless there are compelling reasons in a given case why the court should perform this function. The rationale for such an approach is the frequently expressed policy in favor of trial by jury, springing from constitutional guarantees. As the Supreme Court once stated, “The right to a jury trial in civil cases at common law is a basic and fundamental feature of our system of federal jurisprudence which is protected by the Seventh Amendment. A right so fundamental and sacred to the citizen, whether guaranteed by the Constitution or provided by statute, should be jealously guarded by the courts.” Jacob v. City of New York, 315 U.S. 752, 752-53 [62 S.Ct. 854, 854, 86 L.Ed. 1166] (1942).
Since it was undisputed at trial that in the accused device the forwardmost staple does not touch the anvil surface, if the jury interpreted the claims to mean that “on” requires “touching”, it follows that no reasonable jury, if correctly instructed, could have found literal infringement. (The jury instructions on literal infringement are not included in the Appendix, apparently because they were not referred to in the . briefs, see Fed.Cir.R. 30(a)(2) and 30(b).) \ Thus I do not understand the statement by [the panel majority that the inventor’s asserted claim interpretation was “necessarily arrived at by the jury, and adopted by I the district court”, for the jury verdict is readily understood as pertaining solely to infringement by equivalency, whereby an expansive claim interpretation is not required in order to uphold the verdict.
Senmed charged infringement in terms of the doctrine of equivalents, and the jury was instructed on the issue. The portion of the instructions provided us shows that the jury was told the requirements for finding equivalency, including a description of prosecution history estoppel and a statement of the so-called “reverse” doctrine of equivalents. The jury was instructed that the claims can not be extended to cover that which was in the prior art, or to recover that which was yielded in order to obtain the patent.
Thus I respectfully — disagree with the paneljnajorily-’s-statement-that “[i]n light of the claim and its prosecution history, it is irEfikyaui that Fishbein’s [the prior art] staple is further_„above than Richard-Allan’s”. l£j§_noiJjxele-vani? it is the core db. the question of equivalency,-for it shows that a reasonable,jury could have found that there was room for equivalent .structure between the prior art and ±he..accused device, without violating the doctrine of prosecution history estoppel. As this court said in Bayer Aktiengesellschaft v. Duphar Int’l Research B.V., 738 F.2d 1237, 1243, 222 USPQ 649, 653 (Fed.Cir.1984) “ftlhe fact that the claims were narrowed does not always mean that .the doctrine of file history estoppel cqmple±eLy_prohibits a patentee from recapturing some ..of what was originally claimed”.
In determining if a reasonable jury could have found equivalency without treading upon the prior art, we observe that this issue was the subject of extensive testimony at trial. Witnesses testified that in the accused device the staple was “between 9-to 13- thousandths [of an inch above the 1 anvil] ... somewhat less than a diameter 1 of the staple”, and that in the Fishbein device the distance was “a little over half an inch”. The Fishbein patent describes the distance as “some substantial length, depending upon circumstances”. There appears to have been no dispute on these points. There was substantial evidence on which a reasonable jury could have found equivalency, based on the location of the staple of the accused device within the area above the anvil surface that is not occupied by Fishbein. As was stated recently in
*825Black & Decker, Inc. v. Hoover Service Center, 886 F.2d 1285, 1295 (Fed.Cir.1989):
[T]his court has held that the mere fact of amendment does not necessarily preclude application of the latter doctrine [of equivalents], pointing out that an amendment may result in a limiting effect on the range of equivalents “within a spectrum ranging from great to small to zero.” Hughes Aircraft Co. v. United States, 111 F.2d 1351, 1363, 219 USPQ 473, 481 (Fed.Cir.1983).
See also LaBounty Mfg., Inc. v. United States Int’l Trade Comm’n, 867 F.2d 1572, 1576, 9 USPQ2d 1995, 1999 (Fed.Cir.1989) (“the breadth of the amendment does not necessarily equate with the breadth of the resulting estoppel”). Nothing in the record requires a reasonable jury to limit the claimed invention to a range of equivalents insufficient to encompass the Richard-Allan structure.
The district court wrote a detailed opinion in response to the post-trial motions. The role of the trial judge, as of the appellate panel, is simply to ascertain whether the jury’s verdict is sustainable. It is unwarranted to criticize the district court for not “discussing] the applicable claim language, the specification, or the prosecution history in an effort to arrive at its own claim interpretation as a matter of law”. Nor is such process appropriate to the appellate tribunal. See Orthokinetics, Inc., 806 F.2d at 1572-73, 1 USPQ2d at 1085-86 (it would be “a misunderstanding of our appellate role” for this court to determine what the evidence as a whole supports rather than whether there was substantial credible evidence on which the jury could have based its critical findings.)
Despite the lengthy trial the panel majority, overturning the jury’s verdict, does not address the testimony and exhibits other than that of the inventor Becht, the panel majority appearing to criticize the weight that the district court may have given to Becht’s testimony, based on the district court’s discussion of its denial of Riehard-Allan’s motion for judgment n.o.v. But it is not the district court’s reasoning that is reviewed on appeal from a jury verdict: it is whether the jury’s verdict is sustainable on any reasonable view of the evidence before it. See id. at 1580, 1 USPQ2d at 1091 (“It is not necessary to determine which combination of facts, among those established by substantial evidence at trial and recognized by this court as capable of contributing to a willfullness finding, were relied upon by the jury. This court, and the district court on the motion for JNOY, must uphold the jury determination of will-fullness if there is any set of facts supported by substantial evidence and capable of supporting that jury determination.”) A reasonable jury could have found that a device whose staple rests 9-13 thousandths of an inch above the anvil is equivalent to one whose staple touches the anvil.
This court early in its existence reaffirmed that patent jury trials are subject to the same rules as all jury trials. Railroad Dynamics, 727 F.2d at 1514, 220 USPQ at 937 (“there is no reason for distinguishing the submission of legal questions to a jury in patent cases from the routine submissions of legal issues to juries in other types of cases”); Connell v. Sears, Roebuck & Co., 722 F.2d 1542, 1547, 220 USPQ 193, 197 (Fed.Cir.1983) (“So long as the Seventh Amendment stands, the right to a jury trial should not be rationed, nor should particular issues in particular types of cases be treated differently from similar issues in other types of cases”.) See generally H.T. Markey, On Simplifying Patent Trials, 116 F.R.D. 369, 370 (1987) (“There is neither reason nor authority for employing in a patent trial procedures and practices different from those employed in any other civil trial. Indeed, reason and authority mandate the contrary.”)
As discussed supra, on review the appellate tribunal will ascertain whether a reasonable jury could have reached the verdict that was reached, based on factual findings and legal conclusions that are supportable on the evidence. The record provided us shows that there was substantial evidence to support a jury finding of infringement by equivalency on the claim interpretation most favorable to Richard-Allan, i.e., that “on” requires “touching”. This is the *826claim interpretation reached independently by the panel majority. It is unnecessary to decide if some other claim interpretation could have been adopted by the jury. See Lavender v. Kurn, 327 U.S. 645, 653, 66 S.Ct. 740, 744, 90 L.Ed. 916 (1946) (“the appellate court’s function is exhausted when that evidentiary basis becomes apparent, it being immaterial that the court might draw a contrary inference or feel that another conclusion is more reasonable.”)
Sound administration of justice requires that patent litigation continue to have access to the mainstream of the trial and judicial process. I am distressed at this new disregard of the deference due to jury verdicts, this new uncertainty as to what is required of the trial judge in patent jury trials, this inconsistency with precedent.