dissenting.
I respectfully dissent. In my view, the panel majority confuses its role as law-giver and law-reviewer with the role of fact-weigh-er and fact-deeider. The majority and I agree that the issue is not whether the trial court applied the wrong law (it did not), or whether the jury was wrongly instructed (it was not). As the panel majority correctly notes, the issue is whether, on the totality of the circumstances, Mr. Lough was engaged in “a bona fide effort to bring his invention to perfection, or to ascertain whether it will answer the purpose intended,” City of Elizabeth v. American Nicholson Pavement Co., 97 U.S. 126, 137, 24 L.Ed. 1000 (1877), or whether he was engaged in selling or, on the facts of this case oddly enough for a working mechanic, giving away his invention to members of the public.
This is not a contest between Evinrude (Outboard Marine Corporation) and Mercury Marine (Brunswick), the two big competitors in this field, to see who can market a better engine. If it were, we could expect the combination of engineering and legal staffs on each side to be punctilious about observing the niceties of our prior opinions on how to conduct experiments so as to avoid any possible running afoul of the public use bar. No, this is a home-made improvement by a man with only a high school education who worked on boats and boat engines, including his own, where he kept encountering the problem with these shaft seals that Mercury Marine had failed to solve. He solved it by trial and error, with an ingenious bushing of his own design, and, on his grandfather’s metal lathe, after several tries, fashioned a half-dozen prototype seals that looked like they might do the job.
He put one in his own boat, one in the boat of a close friend, one in the boat of the co-owner of the marine repair shop where he *1124worked, and later put one in the boat of a customer of the shop who was having considerable problems with his stern drive because of the seal difficulty. He gave two to mechanic friends at another marina so they could put them in boats having the same troublesome seal problem, with the understanding they would be used to test the seals in different equipment.
Of course it would have been better for all concerned (except perhaps for Mercury Marine) if Mr. Lough had read our prior opinions before he became an inventor. Then he might have kept detailed lab notes setting out the problem and the possible solutions, and he wisely would have obtained written confidentiality agreements from those allowed to see or use his prototypes. Had he studied our cases first, he no doubt would have developed a detailed questionnaire for the persons to whom he provided the seals, and he would have insisted on periodic written reports. In other words, he would have put in the set of tight controls the majority would have wanted. Instead, he did what seemed appropriate in the setting in which he worked: he waited to hear from his test eases what problems might emerge, and, hearing none, at least none that convinced him he was on the wrong track, he accepted some friendly advice and proceeded to patent his invention.
Yes, he failed to conduct his testing, his experiments, with the careful attention we lawyers, with our clean and dry hands, have come to prefer. But, under all the facts and circumstances, it is more likely than not that he was testing and perfecting his device, rather than simply making it available gratis to members of the general public for what the law calls “public use.” The most that can be said for the majority view is that this is a close question under the totality of circumstances. The ultimate question of what is public use under 35 U.S.C. § 102(b) may be a question of law, but in a given case in which the issue is whether in fact the challenged use was experimental (a complete answer to an infringer’s defense based on a § 102(b) violation), the issue involves a blend of law and fact. This issue, unlike claim construction, is one in which a jury fully participates. Thus the question before us is not whether, on the facts, we are persuaded Lough retained all the control a well-designed test of the seals would have afforded, but whether a reasonable jury, on all the evidence before it, could have arrived at the conclusion it did. Allied Colloids Inc. v. American Cyanamid Co., 64 F.3d 1570, 1577, 35 USPQ2d 1840, 1845 (Fed.Cir.1995) (finding a grant of JNOV improper because “a reasonable jury could have found, applying the correct law, that there was not a public use bar under § 102(b)”). The jury chose to accept Lough’s view of the events, and under that view there was more than enough evidence to support a jury finding that he was testing and perfecting his invention during much of the period leading up to the time he applied for his patent.1 AlS we said in Manville Sales Corp. v. Paramount Systems, Inc., 917 F.2d 544, 551, 16 USPQ2d 1587, 1592 (Fed.Cir. 1990): “When durability in an outdoor environment is inherent to the purpose of an invention, then further testing to determine the invention’s ability to serve that purpose will not subject the invention to a section 102(b) bar.” (citing City of Elizabeth, 97 U.S. at 133-34).
Many of the cases cited by the majority in support of their position are cases in which the inventor made a sale or an offer to sell the product prior to the critical date. See, e.g., RCA Corp. v. Data General Corp., 887 F.2d 1056, 12 USPQ2d 1449 (Fed.Cir.1989); Sinskey v. Pharmacia Ophthalmics, Inc., 982 F.2d 494, 25 USPQ2d 1290 (Fed.Cir.1992), cert. denied, 508 U.S. 912, 113 S.Ct. 2346, 124 L.Ed.2d 256 (1993); Paragon Podiatry Lab., Inc., v. KLM Lab., Inc., 984 F.2d 1182, 25 USPQ2d 1561 (Fed.Cir.1993); In re Hamilton, 882 F.2d 1576, 11 USPQ2d 1890 (Fed. Cir.1989). The record in this case is undis*1125puted that Lough made no sales of his invention until after his patent application was filed. Nor was this simply market testing, rather than product testing, as in In re Smith, 714 F.2d 1127, 218 USPQ 976 (Fed. Cir.1983); and in any event, that was part of the issue presented to the jury.
There is no dearth of cases in this court in which inventors tested their products in various ways before various audiences, and in which we have held that such testing, when it made sense in light of the circumstances, did not constitute public use under section 102(b). See, e.g., Tone Bros. v. Sysco Corp., 28 F.3d 1192, 31 USPQ2d 1321 (Fed.Cir. 1994) (students asked to test functional features of spice containers prior to the critical date; summary judgment of invalidity reversed), cert. denied, — U.S.-, 115 S.Ct. 1356, 131 L.Ed.2d 214 (1995); TP Lab., Inc. v. Professional Positioners, Inc., 724 F.2d 965, 220 USPQ 577 (Fed.Cir.) (orthodontic devices tested on patients prior to critical date; held not invalid even though a fee paid by the patients), cert. denied, 469 U.S. 826, 105 S.Ct. 108, 83 L.Ed.2d 51 (1984); Man-ville Sales Corp., 917 F.2d 544, 16 USPQ2d 1587 (testing of streetlight, conditionally approved for sale, at outdoor site held experimental); see also Moleculon Research Corp. v. CBS, Inc., 793 F.2d 1261, 229 USPQ 805 (Fed.Cir.1986) (inventor of puzzle showed it to a few close colleagues, and allowed one person to use it, prior to the critical date; held not invalid.), cert. denied, 479 U.S. 1030, 107 S.Ct. 875, 93 L.Ed.2d 829 (1987).
Under our standard of review, the jury’s decision to accept Lough’s version of the case is not properly subject to reversal. The trial court correctly denied Brunswick’s JMOL motion, and this court should affirm that denial.
The majority, by unilaterally invalidating the patent on the public use issue, confesses that it thus avoids the knotty problem of how to deal with the infringement question, especially infringement under the doctrine of equivalents. Although I share my colleagues’ unease at addressing this question before we know the Supreme Court’s disposition of Hilton Davis, and am in general sympathy with the views regarding the doctrine of equivalents expressed in the additional remarks, I cannot acquiesce in avoiding the question on the grounds offered here. I believe it is improper and unjust to deny Lough his victory at trial on the question of invalidity under section 102(b), a question properly put to and decided by the jury. (Whether his victory can be sustained on the issue of infringement is not here decided, and I offer no opinion on that question.)
LOURIE, Circuit Judge, additional remarks.
There is another reason why we would exercise our discretion to avoid deciding what appears to be an unnecessary issue of infringement, even though we recognize the value of a complete review of a trial court’s decision by an appellate court that is not the court of last resort. That is the current interim uncertainty concerning certain aspects of the law on infringement. The question of infringement in this case was decided by the jury on the basis of both literal infringement and infringement under the doctrine of equivalents. Were we to face these issues, we might well reverse the judgment on the issue of literal infringement on the ground that the upper portion of the Brunswick upper seal assembly does not supportively receive the upper end of the gear shift shaft, an express limitation of the claims. The question of infringement by equivalence would then become critical. Jury instruction under the doctrine of equivalents, however, was rather limited and preceded our recent in banc decision in Hilton Davis Chemical Co. v. Warner-Jenkinson Co., 62 F.3d 1512, 35 USPQ2d 1641 (Fed.Cir.1995) (in banc), cert. granted, — U.S.-, 116 S.Ct. 1014, 134 L.Ed.2d 95 (1996). Review of the equivalence finding would therefore be problematical.
The Supreme Court has granted certiorari in Hilton Davis and will hear the case in its next term. The Supreme Court has also recently unanimously affirmed our in banc decision in Markman v. Westview Instruments, Inc., 52 F.3d 967, 34 USPQ2d 1321 (Fed.Cir.1995) (in banc), in which we held that construing the scope of a claim is a matter for the court, rather than the jury. See Markman v. Westview Instruments, *1126Inc., - U.S. -, 116 S.Ct. 1384, 134 L.Ed.2d 577, 38 USPQ2d 1461 (1996). The Court based its decision in part on a belief that “[t]he construction of written instruments is one of those things that judges often do and are likely to do better than jurors unburdened by training in exegesis____ The judge, from his training and discipline, is ... more likely to be right, in performing such a duty, than a jury can be expected to be.” Id. at-, 116 S.Ct. at 1395 (citing Parker v. Hulme, 18 F. Cas. 1138, No. 10,740 (CC ED Pa. 1849)).
Thus, it is entirely conceivable that the Court, consistent with its decision in Mark-man, could hold that determination of the scope of a claim beyond its literal language for purposes of determining infringement under the doctrine of equivalents is also a matter for the judge, not the jury. It could do so on the basis that interpreting a claim arguably contrary to the statutory requirement for precision set forth in 35 U.S.C. § 112 requires the discernment of a judge, tantamount to an equitable reformation of the patent. Deciding the infringement phase of this appeal, when it is not clearly necessary, would thus not be prudent. Such would not be the case, of course, were the infringement question to be dispositive of the appeal, but, as indicated above, it is not here.
. The law of this circuit is unequivocal that a “party attacking validity has the burden of proving facts supporting a conclusion of invalidity by clear and convincing evidence.” Ryco, Inc. v. Ag-Bag Corp., 857 F.2d 1418, 1423, 8 USPQ2d 1323, 1327 (Fed.Cir.1988). Whatever the shifLing of the burden of production of evidence at trial may have occurred, the ultimate burden remains with the attacker. The jury verdict leaves no question that Mercury Marine failed to cany its burden.