here's an old us patent case about the wartime binocular lens coating that describes the coating process.
https://casetext.com...lomb-optical-co
"The military services, and particularly the Navy, were particularly anxious to find a practical way of coating binoculars, periscopes and other "light-transmitting" glass surfaces, which should make the film at once tenacious and viable. Indeed, some of the testimony imputes to the services a scarcely understandable estimate of the importance of such a coating. The trouble had been that all the earlier coatings, though their proper composition was known, could be readily scratched or even rubbed off."
Such refs are very interesting. Further on, it says the process was brought to the Naval Gun Factory in 1941:
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There remains only one other point of enough importance to demand discussion: i.e. whether what Lyon had done before November 17, 1941, — a year before his filing date — forfeited his right to a patent under § 102(b) of the Act: that is, whether he had put it in "public use or on sale in this country, more than one year prior to the date of application".
Lyon began to work for the Naval Research Laboratory in January, 1941, trying to find an effective coating. By the middle of June, 1941, he was assured that he "had consistent results as far as hardness and adherence of the film was concerned." He "appeared to be on the right track"; but much testing had still to be done. Nevertheless, "by the first of July" he "was reasonably certain that" he "was getting a hard durable film * * remarkably consistent in the results." "Many, many tests were made," which, however, by September, 1941 had convinced him "that we were in a position to try this thing out on some actual simple instruments." There were a number of old binoculars, which were given to him to coat and it was arranged that these should be introduced surreptitiously, so that the users would not know which had been coated by the new process and which had not.
From binoculars he went to other instruments, so that by October first the "Optical Shop of the Naval Gun Factory" had "completed certain experimental work," and "estimated that $10,000" was "required to provide for equipment and further research."
The "experimental work" had "developed to such a stage as to place the product in production." The officer in charge concluded the letter from which we quote by requesting that the Bureau of Ordnance should approve a "project" for $20,000 both for "production equipment in the shop" and for five units for "repair activities afloat." Such an approval was issued on October 30; but it is to the last degree unlikely that any production should have taken place within three weeks, that was not part of the "further research" deemed necessary on October 1st. At any rate it is clear that the defendant, which had the burden, did not prove its defence. Its theory is that, if with Lyon's consent the Navy exploited the process, it was the same as though he had done so himself; indeed in the end the Navy's exploitation would be far more profitable to him than any sales that he could personally make. It is not necessary to pass upon the legal validity of that interpretation of § 102(b), because, though we should accept it arguendo, it was not proved, as we have just said.
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