[125] Public Law 106-113 s. 4806.

[126] A rare example of a case in which 35 USC § 102(g)(2) was successfully used as a defense to an infringement action is found in Mycogen Plant Science Inc. v. Monsanto Co., 58 USPQ2d 1030 (Fed. Cir. 2001).

[127] This part of the rule dates back at least to Bedford v. Hunt, 3 Fed. Cas 37 (CCD Mass. 1817).

[128] This part of the rule derives from Mason v. Hepburn, 13 App. D.C. (1898).

[129] This part of the rule derives from S.15 of the Act of 1836.

[130] This was the result of a statutory amendment in 1946 to overrule the Supreme Court’s decision in Electric Storage Battery v. Shimadzu, 307 U.S. 5, 41 USPQ 155 (1939) .

[131] This was a consequence of the creation of the North American Free Trade Agreement which was enacted in Public Law 103-82.

[132] This was a consequence of the conclusion of the TRIPS Agreement as part of the Uruguay Round of GATT revisions and was enacted in Public Law 103-405.

[133] The date is earlier for Canada and Mexico. The North American Free Trade Agreement came into effect on January 1, 1994 and the amendments in the law relating to Canada and Mexico became effective on December 8, 1993.

[134] 36 F.2d 292 (CCPA 1929).

[135] The first part of this definition dates back to an 1897 decision of the Court of Appeals for the District of Columbia in Mergenthaler v. Scudder, 11 App D.C. 264 which quotes para 375 of Robinson on Patents, a classic nineteenth century treatise . An alternative formulation in Technitrol Inc, v. United States, 440 F.2d 1363 (Ct Cl 1971) was that the date of conception is the date when the inventive idea "crystallized in all of its essential attributes and becomes so clearly defined in the mind of the inventor as to be capable of being converted into reality and reduced to practice by the inventor or by one skilled in the art.

[136] Burroughs Wellcome Co. v. Barr Laboratories Inc., 40 F.3d 1223 32 USPQ2d 1915 (Fed. Cir. 1994).

[137] Amgen Inc v. Chugai Pharmaceutical Co. Ltd., 927 F.2d 1200, 18 USPQ2d 1016 (Fed. Cir. 19910, Fiers v. Revel, 984 F.2d 1164 (Fed. Cir. 1993).

[138] see for example Vancil v. Arata, 202 USPQ 58 (BPI 1977). In Fiers v. Revel, 25 USPQ 2d 1601 (Fed. Cir. 1993) it was held that for complete conception of an invention of a DNA sequence coding for a particular protein, a written description of the complete DNA sequence is required. The court held that had the DNA been claimed in product by process terms then conception of the process and the utility would have sufficed but "Conception of a substance claimed per se without reference to a process requires conception of its structure, name, formula or definitive chemical or physical properties".

[139] See, for example, Roensch v. Billner, 101 USPQ 281 (CCPA 1954).

[140] The issue is still not entirely clear. In Rey-Bellet v. Engelhardt, 493 F.2d 1380, 181 USPQ 453 (CCPA 1974), the court noted that the Board had taken the position that conception of an invention of a chemical was not complete until a utility for it was conceived. However, the court commented that in its view this was still an open question. It did not have to be decided in that case and surprisingly does not seem to have been decided since.

[141] The need for proof by way of corroboration dates back to at least Mergenthaler v. Scudder, 11 App D.C. 264 (1897) where it was pointed out that if drawings were relied upon to establish a date of conception they had to show “complete” conception and be “free of ambiguity or doubt”. An example of a case where the evidence was open to a number of plausible interpretations and so too ambiguous to sustain a finding that a date of conception had been established is Gould v. Schawlow, 363 F.2d 908, 150 USPQ 634 (CCPA 1966) where Gould’s notes were held to be too ambiguous to show that he invented the laser. See also Boroughs Wellcome v. Barr, 40 F.3d 1223, 32 USPQ2d 1915 (Fed. Cir. 1994). Corroboration of a third party's claim to prior invention when 35 USC § 102(g) is pleaded as a defense to an infringement action may, however, not always be needed if the witness has nothing to gain from proving the date in question. Thomson S. A. v. Quixote Corp, 49 USPQ2d 1530 (Fed. Cir. 1999).

[142] 34 App D.C. 141 (1909).

[143] See, for example, Landon v. Ginzton, 102 USPQ 230 (CCPA 1954).

[144] RCA v. Philco, 275 F.Supp. 172, 154 USPQ 570 (D. N.J. 1967),

[145] Cooper v. Goldfarb, 154 F.3d 1321 47 USPQ2d 1896 (Fed. Cir. 1998). One party had sent the other party some fibrils to test. The count specified the length of the fibrils. The first party had never expected the material sent to have the fibril lengths set out in the count or had their lengths measured.

[146] RCA v. Philco, 275 F.Supp. 172, 154 USPQ 570 (D. N.J. 1967).

[147] Friction Division Products Inc, v. E.I. DuPont, 658 F.Supp. 998 3 USPQ2d 1775(D. Del. 1987).

[148] As set out in 35 USC 112 - see Pritchard v. Loughlin, 361 F.2d 483, 149 USPQ 841 (CCPA 1966).

[149] Automatic Weighing Machine v. Pneumatic Scale Co 166 F. 288 (1st Cir. 1909). See also for example Hann v. Venetian Blind Company, 45 USPQ 292 (9th Cir. 1940). It seems that in order to be effective as a constructive reduction to practice, it may not be necessary for the application to meet the “best mode” requirement. Cromlish v. D.Y., 57 USPQ2d (Bd of Apps 2000).

[150] Corona Cord Tire Co v. Dovan Chem Corp, 276 US 358 (1928), Kawai v. Metlesics, 480 F.2d 880, 178 USPQ 659 (CCPA 1976).

[151] Thus, sickness or poverty of the inventor may be taken into account.

[152] Hull v. Davenport 90 F.2d 103, 33 USPQ 506 (CCPA 1937).

[153] 760 F.2d 1270, 226 USPQ 224 (Fed. Cir. 1985).

[154] The majority in that case held that where, even where there was a long delay after conception and reduction to practice before filing a patent application, where diligent preparation of the patent application began before the rival party's date of conception, the delay should not be held to be a suppression, concealment or abandonment of the application. The case distinguished Peeler v. Miller (noted below) on the ground that in that case, the rival's date of conception was during the period of inactivity. This may be relevant to the question of diligence, but is it really satisfactory when considering suppression?

[155] Young v. Dworkin, 489 F.2d 1277, 180 USPQ 388 (CCPA, 1974). In this case the delay arose from the need to find a machine that could make the product and the losing inventor had not been particularly diligent about doing so.

[156] See, for example, International Glass Co v. United States, 161 USPQ 116 (Ct Cl 1966) where the prior inventor documented his invention but did nothing to publicize or develop it. “The courts have consistently held that an invention, though completed, is deemed abandoned, suppressed or concealed if, within a reasonable time after completion, no steps are taken to make the invention publicly known.” The question of what is reasonable depends on the facts. For example in Lutzker v. Plet, 6 USPQ2d 1370 (Fed. Cir. 1988) fifty-one months delay was held to be unreasonable when the time was spent on commercialization issues rather than technical ones that appeared in the patent application.

[157] See, for example, Kendall v. Winsor, 62 U.S. 322 (1858). However, the cases frequently fail to distinguish between the current approach to 35 USC § 102(b) issues where prior secret use by another is not a bar although prior secret use by the applicant is a bar and the question of concealment under 102(g). It is, however, clear that ever since Pennock v. Dialogue that the courts have generally taken a dim view of those who exploit their inventions in secret.

[158] Mason v. Hepburn, 13 App DC 86 (D.C. Cir. 1898).

[159] Peeler v. Miller, 535 F.2d 647, 190 USPQ 117 (CCPA 1976). The court noted that although mere delay could not be equated with suppression, in this case, the delay was not "mere" and that the inventor's employer was to blame by allowing its patent department to become under staffed.