Definition[edit | edit source]

U.S. patent law[edit | edit source]

Prosecution laches is an "unreasonable and unexplained delay in prosecution."[1]

The doctrine of prosecution laches is grounded in the need to strike an appropriate balance between the public's interest in encouraging invention with the public's competing interest in 'the free public enjoyment of the useful invention.' It is an objective measure of reasonableness, applied to a patent applicant's explanation for his delay, that determines whether that delay is legitimate.[2]

"The court must evaluate how a reasonable patent applicant would prosecute his patent under plaintiff's circumstances. The inquiry is not directed at plaintiff's subjective attitude toward the prosecution.”[3] "The applicant's pecuniary interest in the patent cannot by itself make an otherwise unexplained delay in prosecution reasonable."[4]

The goals of prosecution laches . . . are twofold: to block a patent applicant from (1) unreasonably delaying the issuance of a patent and attendant publication of an invention for the purpose of maximizing its commercial value and (2) 'depriv[ing] the public of free use of the patent which the law intended' for a period of time in excess of the monopoly period already provided by the patent laws. In other words, prosecution laches prevents patent applicants from 'unduly postpon[ing] the time when the public [can] enjoy the free use of the invention’ by strategically delaying the issuance of the patent to their own commercial advantage. . . . Prosecution laches is not a doctrine, like traditional laches, aimed to protect specific competitors. It rather serves the broader public interests in the timely issuance of patents. Because prosecution laches applies to the conduct of a patent applicant prior to the issuance of a patent, the doctrine cannot be aimed at protecting specific infringers or potential infringers from prosecutorial delay, because there can be no patent infringement until a patent has issued."[5]

"[T]he burden of proof on a defendant raising the defense of prosecution laches should be no higher than that required to raise other equitable defenses in patent cases, including traditional laches."[6]

References[edit | edit source]

  1. In re Bogese II, 303 F.3d 1362, 1367, 64 U.S.P.Q.2d (BNA) 1448 (Fed. Cir. 2002) (full-text).
  2. Reiffin v. Microsoft Corp., 270 F.Supp.2d 1132, 1153 (N.D. Cal. 2003) (full-text) (citations omitted).
  3. Id. at 1155.
  4. Id. at 1153.
  5. Id. at 1154.
  6. Id. at 1155.
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