Held: 1. A patent is invalid for indefiniteness if its claims, read in light of the patent’s specification and prosecution history, fail to inform, with reasonable certainty, those skilled in the art about the scope of the invention. The parties agree that definiteness is to be evaluated from the perspective of a person skilled in the relevant art, that claims are to be read in light of the patent’s specification and prosecution history, and that definiteness is to be measured as of the time of the pa tent application. The parties disagree as to how much imprecision §112, ¶2 tolerates.
Section 112’s definiteness requirement must take into account the inherent limitations of language. See Festo Corp. v. Shoketsu Kinzo- ku Kogyo Kabushiki Co., 535 U. S. 722, 731. On the one hand, some modicum of uncertainty is the “price of ensuring the appropriate in centives for innovation,” id., at 732; and patents are “not addressed to lawyers, or even to the public generally,” but to those skilled in the relevant art, Carnegie Steel Co. v. Cambria Iron Co., 185 U. S. 403, 437. At the same time, a patent must be precise enough to afford clear notice of what is claimed, thereby “ ‘appris[ing] the public of what is still open to them,’ ” Markman v. Westview Instruments, Inc., 517 U. S. 370, 373, in a manner that avoids “[a] zone of uncertainty which enterprise and experimentation may enter only at the risk of infringement claims,” United Carbon Co. v. Binney & Smith Co., 317 U. S. 228, 236. The standard adopted here mandates clarity, while recognizing that absolute precision is unattainable. It also accords with opinions of this Court stating that “the certainty which the law requires in patents is not greater than is reasonable, having regard to their subject-matter.” Minerals Separation, Ltd. v. Hyde, 242 U. S. 261, 270. Pp. 8–11.
2. The Federal Circuit’s standard, which tolerates some ambiguous claims but not others, does not satisfy the statute’s definiteness re quirement. The Court of Appeals inquired whether the ’753 patent’s claims were “amenable to construction” or “insolubly ambiguous,” but such formulations lack the precision §112, ¶2 demands. To tolerate imprecision just short of that rendering a claim “insolubly ambigu ous” would diminish the definiteness requirement’s public-notice function and foster the innovation-discouraging “zone of uncertainty,” United Carbon, 317 U. S., at 236, against which this Court has warned. While some of the Federal Circuit’s fuller explications of the term “insolubly ambiguous” may come closer to tracking the statuto ry prescription, this Court must ensure that the Federal Circuit’s test is at least “probative of the essential inquiry.” Warner-Jenkinson Co. v. Hilton Davis Chemical Co., 520 U. S. 17, 40. The expressions “in solubly ambiguous” and “amenable to construction,” which permeate the Federal Circuit’s recent decisions concerning §112, ¶2, fall short in this regard and can leave courts and the patent bar at sea without a reliable compass. Pp. 11–13.
3. This Court, as “a court of review, not of first view,” Cutter v. Wil- kinson, 544 U. S. 709, 718, n. 7, follows its ordinary practice of re manding so that the Federal Circuit can reconsider, under the proper standard, whether the relevant claims in the ’753 patent are suffi ciently definite, see, e.g., Johnson v. California, 543 U. S. 499, 515. Pp. 13–14.
715 F. 3d 891, vacated and remanded. G INSBURG , J., delivered the opinion for a unanimous Court.
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