Sonix Technology Co., Ltd. v. Publications International, 844 F.3d 1370

Sonix owns U.S. Patent No. 7,328,845, which claims a system for encoding information on object surfaces using a "graphical indicator" (e.g., a matrix of tiny dots) that is intended to be "visually negligible."
The specification describes design guidance (differentiability, brightness, homogeneity), suggests micro-unit sizes ("so tiny that only a microscope apparatus can detect it"), and provides two numerical examples (e.g., 3,000 or 6,000 cells/cm² with specified fill ratios).
The PTO confirmed patentability during an ex parte reexamination and allowed multiple asserted claims; a later reexamination rejected and then withdrew rejections after an expert declaration showing the claimed indicator was visually negligible compared to prior art.
Sonix sued several publishers for infringement; defendants litigated invalidity and at summary judgment argued the term "visually negligible" rendered asserted claims indefinite under 35 U.S.C. § 112 ¶ 2.
The district court granted summary judgment of indefiniteness, finding "visually negligible" purely subjective and lacking objective boundaries; Sonix appealed.
The Federal Circuit reviewed de novo and reversed, holding that the claim term, read in light of the specification and prosecution history, gives those skilled in the art reasonable certainty about scope.

Issue	Plaintiff's Argument (Sonix)	Defendant's Argument (Appellees)	Held
Whether the claim term "visually negligible" renders the asserted claims indefinite under § 112 ¶ 2	The specification (requirements and examples) and prosecution/reexamination history give a skilled artisan reasonable certainty to apply the term; it depends on human visual perception (an objective baseline) not pure opinion	Term of degree with no objective test; depends on subjective individual perception and thus is indefinite	Reversed: term is not indefinite when read with the specification and prosecution history; claims survive indefiniteness challenge

Nautilus v. Biosig Instruments, Inc., 134 S. Ct. 2120 (definiteness requires that claims inform skilled artisans of scope with reasonable certainty)
Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364 (terms of degree not inherently indefinite; "unobtrusive" held indefinite where specification lacked guidance)
Enzo Biochem, Inc. v. Applera Corp., 599 F.3d 1325 (specification examples and selection criteria can render terms of degree definite)
Datamize, LLC v. Plumtree Software, Inc., 417 F.3d 1342 ("aesthetically pleasing" indefinite where no objective guidance existed)
Warsaw Orthopedic, Inc. v. NuVasive, Inc., 778 F.3d 1365 (reliance on human perception does not necessarily render a claim indefinite)
Info-Hold, Inc. v. Applied Media Techs. Corp., 783 F.3d 1262 (prosecution/reexamination history may inform definiteness analysis)