In this patent infringement action tried to a jury, the district court directed the grant of judgment as a matter of law in favor of the defendant American Cyanamid Company (“Cyanamid”), upon completion of the case in chief presented by the plaintiffs Allied Colloids Inc. and Allied Colloids Ltd. (collectively “Colloids”). 1 The court held that a reasonable jury could reach only the verdict that the patents in suit, United States Patents Nos. 4,720,346 and 4,943,378, were invalid based on the public use bar of 35 U.S.C. § 102(b). The principal issue on appeal is the correctness of that judgment. An additional issue is the correctness of the district court’s ruling that Colloids’ patents are unenforceable for inequitable conduct because Colloids did not tell the Patent and Trademark Office (“PTO”) about this public use.
I
THE PUBLIC USE BAR
In granting judgment as a matter of law after presentation of the plaintiffs case, the plaintiffs facts must be accepted as established and all reasonable inferences from those facts must be drawn in the plaintiffs favor. Rule 50(a)(1), Fed.R.Civ.P., provides that if
a party has been fully heard on an issue and there is no legally sufficient evidentia-ry basis for a reasonable jury to find for that party on that issue, the court may determine the issue against that party and may grant a motion for judgment as a *1573 matter of law against that party with respect to a claim or defense that cannot under the controlling law be maintained or defeated without a favorable finding on that issue.
See generally Anderson v. Liberty Lobby, Inc.,
The grant of a Rule 50(a) motion is given plenary review on appeal.
Parker v. Prudential Ins. Co.,
Thus the verdict may be directed after the plaintiffs case is presented, when it is clear that completion of the trial is unnecessary in that the only sustainable verdict could be in favor of the defendant. There is, however, practical weight in favor of completing the trial, lest the directed verdict not be sustained on appeal; as noted in Dace v. ACF Indus., Inc.:
This case illustrates again that it is usually better practice for a district court, faced with a motion for directed verdict, to allow the case to go to the jury, and address the issue by way of judgment n.o.v. if necessary. The jury may find for the moving party, in which case the issue disappears. If the verdict is against the moving party, and if judgment n.o.v. is granted, and if this Court decides on appeal that it should have been denied, the verdict can simply be reinstated, and no new trial is necessary.
A
The occurrence of the events on which the district court’s judgment rested is not in dispute. However, the factual inferences and legal conclusions that the court drew from these events are challenged. In brief outline:
Colloids is a purveyor of sewage treatment materials. The patents in suit are directed to certain polymeric flocculents and the method of treating sewage with these materials. Colloids told officials of the City of Detroit that these materials, which were developed in England, might be useful in treating Detroit municipal waste. Colloids had previously treated Detroit waste, but had lost the business. At Colloids’ invitation samples of Detroit sludge were sent to England for testing. After some favorable test results in England, about twenty samples of Colloids’ sewage treatment materials were brought to Detroit for testing on fresh Detroit sewage. These samples were about two to four ounces in size. They were tested on April 16-17, 1985, in a laboratory located at a Detroit sewage treatment plant. The tests showed promising results for some of Colloids’ products. Additional laboratory tests were conducted in Detroit in July 1985, and plant-scale trials were conducted in Detroit in December 1985. Colloids’ patent application was filed in the United States on April 23, 1986; thus only the first series of tests is relevant to the asserted public use bar, i.e. the April 16-17, 1985 tests.
The district court held, after the plaintiffs case, that the tests on April 16-17 were an *1574 invalidating public use as a matter of law, on the principal grounds that the tests had a “commercial objective” and were not performed under a confidentiality agreement with the City of Detroit. Colloids argued that the tests were of an experimental nature. The district court did not disagree, but held that the experimental nature did not avoid the public use bar because the activity was “commercially motivated.”
B
35 U.S.C. § 102 provides that a person is entitled to a patent unless
(b) the invention was ... in public use or on sale in this country, more than one year prior to the date of the application for patent in the United States.
A “public use” for the purpose of barring access to the patent system is a use more than a year before the patent filing date, whereby a completed invention is used in public, without restriction and in circumstances other than “substantially for the purposes of experiment.”
Smith & Griggs Mfg. Co. v. Sprague,
The law recognizes that the inventor may test the invention, in public if that is reasonably appropriate to the invention, without incurring a public use bar. In
City of Elizabeth v. American Nicholson Pavement Co.,
When the subject of invention is a machine, it may be tested and tried in a building, either with or without closed doors. In either case, such use is not a public use, within the meaning of the statute, so long as the inventor is engaged, in good faith, in testing its operation. He may see cause to alter it and improve it, or not. His experiments will reveal the fact whether any and what alterations may be necessary.
Thus the public use bar of § 102(b) requires that (1) the invention was used in public and (2) the use was not primarily experimental in purpose. The determination of these aspects requires considering and weighing such factors as the nature of the activity that occurred in public; the public access to and knowledge of the public use; whether there was any confidentiality obligation imposed on persons who observed the use; whether progress records or other indicia of experimental activity were kept; whether persons other than the inventor or acting for the inventor conducted the experiments; how many tests were conducted; the scale of the tests compared with commercial conditions; the length of the test period in comparison with tests of similar products; and whether payment was made for the product of the tests.
See Baker Oil Tools, Inc. v. Geo Vann, Inc.,
Patent invalidity based on public use is required to be proved by clear and convincing evidence.
Moleculon Research Corp. v. CBS, Inc.,
Invalidity under 35 U.S.C. § 102(b) is an affirmative defense and therefore the burden of proof in this case was on Cyanam-id.
See TP Labs.,
Credibility determinations, the weighing of evidence, and the drawing of legitimate inferences from the facts are jury functions, not those of a judge, whether he is ruling on a motion for summary judgment or for a directed verdict. The evidence of the non-movant is to be believed, and all justifiable inferences are to be drawn in his favor.
The district court held that the April 16-17 tests in the Detroit sewage treatment laboratory were an invalidating public use even if the tests were for purposes of experimentation, for the reason that they were “commercially motivated.” This was an error of law.
See Manville Sales,
C
Colloids presented testimony that the April 16-17 tests were part of its project to ascertain which if any of the various formulations would successfully treat Detroit sewage. Witnesses testified that the earlier tests in England, using sludge that had been shipped from Detroit, gave useful preliminary results, and led to continuing the testing using fresh Detroit sewage. There was testimony that the biological nature of sewage varies; that the results of laboratory testing did not guarantee the same result with testing in situ; and that site testing of Detroit’s sewage was required.
It was not contradicted, during the plaintiffs ease, that no Detroit personnel watched the tests, or knew the composition of the products that were being tested, or knew the test results. The tests were done in an area away from the actual sewage treatment operation. Colloids’ witnesses testified that a City technician occasionally entered the room for other purposes, but did not observe and had no connection with these tests. The tests were conducted by Colloids’ personnel, who kept a research log of the experiments.
The tests were not observed by anyone other than Colloids’ employees. Mr. Whit-well, Colloids’ Technical Services Manager who was present at the tests, testified that no one from the City of Detroit was involved in the tests or knew what products were being tested. Mr. Field, an inventor who was not himself present at the tests, testified that representatives of the City of Detroit “were there” at the municipal plant, but were not “observing the experiments.” No witness testified that anyone other than Colloids’ employees conducted or observed the experiments. It was undisputed that Colloids maintained strict control over the test samples, and that those samples were small in the context of municipal waste treatment.
In
Grain Processing Corp. v. American Maize-Products Co.,
The district court referred to the absence of a written confidentiality agreement between Colloids and the City of Detroit. Although a written promise of confidentiality is a factor to be considered in appropriate circumstances, such as when persons other than the patentee conduct the experiments,
see Hycor,
That Colloids hoped to obtain Detroit’s business is not dispositive of the § 102(b) analysis. Undoubtedly the Detroit tests were conducted in order to determine whether Colloids had or could make products that would satisfactorily treat Detroit sewage. Such testing at the potential customer’s site does not raise a public use bar as a matter of law. All of the circumstances must be considered, to ascertain whether on the entirety of the evidence it has been proved that the patented invention was publicly used.
The district court apparently concluded that Colloids itself viewed its April 16-17 tests as a bar under § 102(b). The court referred to a letter from Colloids’ British patent attorney, written in March 1985, stating that the patent application should be filed before a “commercial sampling” in Detroit “the end of April.” Colloids argues that this letter does not establish the nature of the April 16-17 tests. We agree that this letter was inadequate ground for the grant of judgment as a matter of law. Cautionary advice from a foreign patent attorney, advice that was not implemented, is not an admission of United States law or fact.
A public use under § 102(b) does not start the one-year period until the invention has left the experimental stage.
See Manville Sales,
The district court also stated that it was not relevant that Colloids prepared detailed records of the tests. Precedent teaches that this action is highly relevant, for the keeping of detailed test records is a routine indicium oí the experimental mode. As in
TP Labs.,
such facts “indicate the inventor was testing the device, not the market.”
The law recognizes
an inventor’s need to test the invention, to ascertain whether the work is complete or further changes should be made, and to show that the invention will work for its intended purpose.... [S]uch testing and development may encompass or even require disclosure to the public, without barring the inventor’s access to the patent system.
Id.
at 1563, 4 USPQ2d at 1213.
See also, e.g., Grain Processing,
in such a case, that the machine should be put up and used only in the inventor’s own shop or premises. He may have it put up and used in the premises of another, and the use may inure to the benefit of the owner of the establishment. Still, if used under the surveillance of the inventor, and for the purpose of enabling him to test the machine, and ascertain whether it will answer the purpose intended, and make such alterations and improvements as experience demonstrates to be necessary, it will still be a mere experimental use, and not a public use, within the meaning of the statute.
D
On the evidence adduced during Colloids’ ease in chief, construed as required by Rule 50(a)(1), a reasonable jury could have found, applying the correct law, that there was not a public use bar under § 102(b).
See Orthokinetics, Inc. v. Safety Travel Chairs, Inc.,
II
INEQUITABLE CONDUCT
The district court held the patents in suit permanently unenforceable for inequitable conduct. The court ruled that Colloids had the obligation to tell the PTO of its testing activities in Detroit on April 16-17, 1985. This ruling was based on the letter written by Colloids’ British patent attorney in March 1985, advising that a patent application should be filed before “commercial sampling” in Detroit “the end of April.” Cyan-amid’s motion for judgment as a matter of law was granted on this issue, at the close of the plaintiff’s case in chief.
A
The issue of inequitable conduct was not the subject of testimony in Colloids’ case in chief. It appears to have been raised on quite short notice, in connection with Cyan-amid’s Rule 50(a)(1) motion. Cyanamid does not appear to dispute this point, confirming in its brief that Colloids had been served with “Cyanamid’s motion papers, which thoroughly briefed the issue of inequitable conduct, on the previous evening.”
The district court stated from the bench that “I didn’t rest my decision on the duty to bring [the April 1985 tests] to the attention of the Patent Office.” However, in the court’s subsequent written Order this was the only reason given for the ruling of inequitable conduct. The court’s Order referred to the British patent attorney’s letter of March 29, 1985, about which he had testified in connection with the issue of experimental use and his understanding of the forthcoming “commercial sampling.” The district court apparently concluded (the Order does not explain) that if Colloids’ British patent attorney believed that there was a public use bar under United States law, he should have told the PTO.
The British patent attorney was not asked about his statement during cross-examination. For example, he was not asked why he did not file a patent application as the letter proposed. Colloids correctly points out that it was not required to foresee and respond to an issue that had not been raised. Rule 50(a) authorizes a directed verdict against a party only if the party has been fully heard on the issue. The notes to Rule 50(a)(1) states:
In no event, however, should the court enter judgment against a party who has not been apprised of the materiality of the dispositive fact and been afforded an opportunity to present any available evidence bearing on that fact.
*1578 Fed.R.Civ.P. Rule 50 advisory committee’s note (1991 Amendment). It is apparent that this criterion was not met.
B
To establish unenforceability based on inequitable conduct the challenger must prove, by clear and convincing evidence, that material information was intentionally withheld for the purpose of misleading or deceiving the patent examiner.
Kingsdown Medical Consultants, Ltd. v. Hollister Inc.,
It was to mitigate the “plague” whereby every patentee’s imperfections were promoted to “inequitable conduct” that this court reaffirmed that both materiality and culpable intent must be established. As stated in
Kingsdown,
“all of the evidence, including evidence indicative of good faith, must indicate sufficient culpability to require a finding of intent to deceive.”
In view of our holding that a public use bar is not supportable on the evidence that was adduced, the failure to tell the examiner about this purported bar can not be deemed material and culpable in terms of the requirements of Rule 50(a)(1). It is not inequitable conduct to omit telling the patent examiner information that the applicant in good faith believes is not material to patentability. Whatever might be established upon trial of the issue is not before us; but the predicate facts of materiality and intent can not be inferred in the circumstances that here existed. The judgment of invalidity or unenforce-ability based on inequitable conduct must be vacated.
Ill
THE MOTION TO STRIKE
Cyanamid moves to strike portions of Colloids’ reply brief, stating that Colloids discusses new issues, not raised in its main brief. The portions to which Cyanamid objects refer to an Order of the district court dated July 23, 1993, denying Cyanamid’s motion for attorney fees. This Order was received by Colloids after Colloids filed its opening brief in this court on July 23, 1993, and was not mentioned by Colloids in that brief. Cyanamid in its responsive brief filed September 3, 1993, referred to material that Colloids had filed in the district court in response to the attorney fee motion, some of which was contained in the joint appendix. Cyanamid did not mention on September 3 that the district court had denied the motion on July 23. Colloids in its reply brief discusses the denial. Cyanamid’s motion states that Colloids improperly raised a new issue.
We discern no significant new issue raised in Colloids’ reply brief. The district court’s Order of July 23 was properly brought to our attention, for motions and orders filed in the district court after the date of the order appealed from “may affect ... consideration of the various issues presented.”
Bryant v. Carleson,
The district court’s Order is relevant to this case, and was appropriately brought to our attention. Cyanamid’s motion to strike serves as a responsive argument and, although irregular, is received for that purpose. The motion to strike and for attorney fees is denied.
Conclusion
The judgment under Rule 50(a)(1) of invalidity based on public use, and of unenforce- *1579 ability based on inequitable conduct, is vacated. The case is remanded for further proceedings, consistent with this opinion.
Costs to Colloids.
VACATED AND REMANDED.
Notes
. Allied Colloids Inc. v. American Cyanamid Co., No. 92-1658A (E.D.Va. June 7, 1993) (Order). Allied Colloids Ltd. is the British parent company and Allied Colloids Inc. is its American subsidiary.
