Conception, Testing, Reduction to Practice: When is it Really on Sale?

Journal of the Patent & Trademark Society, Vol. 80, p. 305, 1998

U. of Pittsburgh Legal Studies Research Paper Series

16 Pages Posted: 15 Jul 2009

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At what stage in the developmental process of an invention can it be said that the invention is capable of being put "on sale" within the meaning of Section 102(b) of the U.S. Patent Act? The Federal Circuit's on sale decisions have failed to produce any clear consensus on the extent-of-development issue; the court's view on the degree of completion required has varied from case to case in almost cyclical fashion. Although its early decisions appeared to adopt a requirement that an invention be built and tested before the on sale bar could be triggered, the Federal Circuit in 1987 rejected that notion in its UMC Electronics decision. During 1996-97, the court decided a series of on sale cases in which the requisite degree of development varied from "completed" to "substantially completed" to "no physical embodiment necessary."

The Federal Circuit's erratic treatment of the extent-of-development issue has not gone unnoticed. On March 9, 1998, the U.S. Supreme Court granted the petition for writ of certiorari in the most recent of the Federal Circuit’s on sale decisions, Pfaff v. Wells. In anticipation of the Supreme Court’s decision, this article argues that the need for certainty in identifying the commencement of the one year statutory clock, coupled with the legislative and decisional history of Section 102(b), suggest that an invention should be “complete” before its offer or sale can trigger the on sale bar. Because the patent laws do not define when an invention has been completed, the most practical solution is to require an actual reduction to practice, defined by the existence of a physical embodiment of the invention known to work for its intended purpose. Admittedly, imposing an actual reduction to practice requirement may artificially postpone the triggering of the Section 102(b) bar in certain instances and result in some commercial exploitation beyond the statutory period. But on balance, such costs on the patent system will be outweighed by the benefits of relative certainty, enhanced communications between inventors and prospective customers, and greater progress of the useful arts through the filing of patent applications on fully-developed inventions.

Keywords: on sale, offer for sale, statutory bar, loss of right, experimental use, research tools, U.S. patent system, patent claims, patentability requirements, development of inventions, 35 U.S.C. Section 102(b), Federal Circuit, Pfaff v. Wells, undue commercialization

Suggested Citation

Mueller, Janice M., Conception, Testing, Reduction to Practice: When is it Really on Sale?. Journal of the Patent & Trademark Society, Vol. 80, p. 305, 1998, U. of Pittsburgh Legal Studies Research Paper Series, Available at SSRN:

Janice M. Mueller (Contact Author)

Chisum Patent Academy ( email )

951 Delong Road
Lexington, KY 40515
United States
8553244786 x2 (Phone)


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