Patents are required to “conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as [the] invention.” 35 U. S. C. §112. This requirement, known as "definiteness," dates back to the first Patent Act in 1790 and serves an important public notice function ensuring that patents afford clear notice of what is claimed as one's invention. The "definiteness" requirement apprises the public of what is still open to them and, absent this requirement, there would be a zone of uncertainty that inventors and companies may enter only at the risk of infringing another inventor's patent. Recently, the Supreme Court weighed in issuing an important decision, Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120 (2014), rejecting the existing test and creating a new standard for determining whether patent claims fail to meet the definiteness requirement and are thus invalid. This past week, the Federal Circuit heard argument on remand in the Nautilus case. Many are hopeful that this decision will be an important next step in determining how the new standard should be applied in district courts and the Patent Office, including, how the decision may affect strategies used in inter partes review proceedings ("IPR").

Before the Supreme Court's Nautilus decision issued this summer, the test was that a patent claim passes the §112, ¶2 “definiteness” threshold so long as the claim is “amenable to construction,” and the claim, as construed, is not “insolubly ambiguous.” Working under this test, patent practitioners and courts struggled with what it meant for a claim to be "insolubly ambiguous." In Nautilus, the Supreme Court concluded that the Federal Circuit’s formulation, which tolerates some ambiguous claims but not others, does not satisfy the statute’s definiteness requirement. The Court concluded that that this test would diminish the definiteness requirement’s public notice function and cause confusion in its application by district courts. In place of the "insolubly ambiguous" standard, the Court held that a patent is invalid for indefiniteness if its claims, read in light of the specification and prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention.

During oral argument last week, the Federal Circuit panel indicated that there were a number of issues that must be resolved in light of the Supreme Court’s decision in Nautilus. Among them were how much precision is meant by “reasonable certainty,” what type of evidence should be permitted in deciding an issue of indefiniteness, and to what extent expert testimony may be used. As for the first issue, the Federal Circuit panel explored various criteria that courts have used for assessing definiteness both before and after the Supreme Court's Nautilus decision, including:

  • Whether a claim is sufficiently definite if "the meaning of the claim is discernible, even though the task may be formidable and the conclusion may be one over which reasonable persons will disagree . . . .” Exxon Research and Eng’g Co. v. U.S., 265 F. 3d 1371, 1375 (Fed. Cir. 2001);
  • Whether a claim is sufficiently definite if “the claim language and the prosecution history leave no reasonable uncertainty about the boundaries of the terms at issue, even considering certain aspects of the specification that could engender confusion when read in isolation.” Ancora Techs. v. Apple, Inc., 744 F. 3d 732, 737 (Fed. Cir. March 3, 2014);
  • Whether a claim is sufficiently definite if the claim language “might mean several different things and ‘no informed and confident choice is available among the contending definitions . . . .’” Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120, 1230 n.8 (quoting Every Penny Counts, Inc. v. Wells Fargo Bank, N.A.,4 F. Supp. 3d 1286, 1291 (M.D. Fla. Mar. 5, 2014)); and
  • Whether a claim is sufficiently definite if “when read in light of the specification and the prosecution history, [it] … provide[s] objective boundaries for those of skill in the art.” Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364, slip op. at 15 (Fed. Cir. Sep. 10, 2014).

These important issues shaping the “definiteness” doctrine may also affect IPR proceedings in the Patent Office. Although the AIA does not specifically allow indefiniteness rejections in post-grant review proceedings, the Board may factor § 112 issues into its analysis. For example, where a patent does not provide sufficient structure to define a means-plus-function limitation, the Board may conclude that it is unable to construe the claim and may terminate the IPR. See, e.g., Blackberry v. MobileMedia Ideas, IPR2013-00036, Paper 65 at 12-20 (March 7, 2014). Depending on how the Federal Circuit applies the Nautilus test, this impending ruling may have a major effect on invalidity challenges both in district court litigation as well as in post-grant review proceedings, in addition to substantially changing the way in which patent claim terms and specifications are drafted during prosecution.