Claim Term “Visually Negligible” Has Some Objective Measure and Is Sufficiently Definite in View of Specification

February 2017

Sonix Technology Co., Ltd. v. Publications International, Ltd., No. 2016-1449 (Fed. Cir. Jan. 5, 2017)


In Sonix, the Federal Circuit held that the term “visually negligible” was sufficiently definite as it appeared in the claims because, although it was a term of degree, it was not a wholly subjective term in view of the specification and prosecution history, and the fact that both parties’ experts applied the term without apparent confusion.

Sonix was the assignee of a patent including claims directed to a graphical indicator to encode information the surface of an object that is “visually negligible.” For example, in place of bar codes on books, the patented system would use an information-encoding matrix of dots, arranged in repeating “micro-units” on the book’s cover that would be small enough that a human eye could not distinguish one unit from others.

Sonix sued a group of book publishers including Publications International, SD-X Interactive, Inc., Encyclopedia Britannica, Inc., and Herff Jones, Inc., alleging patent infringement. During claim construction before the district court, the publishers identified 26 claim terms they allegedly contended were indefinite, but did not include the term “visually negligible.” The publishers at one point sought a construction of that term, but later agreed to a plain meaning construction. Both sides submitted expert reports, with both experts applying the term without difficulty. However, during the deposition of Sonix’s expert, he admitted that there was no objective standard for measuring whether a graphical indicator was “visually negligible.” In view of Sonix’s expert’s admission, the publishers amended their invalidity contentions and moved for summary judgment. The district court found that the claims were indefinite, holding that whether an indicator was “visually negligible” was purely subjective and that the claim language did not provide guidance as to its meaning.

The Federal Circuit reversed on appeal. Contrary to the district court’s findings, “visually negligible” was not defined solely in terms of a person’s subjective tastes or opinions. It could be measured objectively in terms of what could be seen by the human eye. This was supported by the specification, which contained an exemplary design, detailed requirements for making graphical indicators “visually negligible” and specific examples of “visually negligible” indicators. The specification was further supported by the prosecution history, including the history of two reexaminations, in which examiners and experts applied the term without any apparent uncertainty as to its scope or construction. The court further pointed to the fact that much of the litigation had proceeded without identifying the term as potentially indefinite, and concluded that Sonix’s expert’s apparent admission was not persuasive in view of the strong intrinsic evidence.

Key Takeaway: Claim terms of degree may still be sufficiently definite under the Patent Act if they can be understood in view of some objective measure, and are adequately supported by detailed disclosures in the specification and prosecution history. Practitioners must be careful to avoid using terms that turn entirely on a person’s tastes or opinions. Accused Infringers must be careful to identify potentially indefinite terms early in litigation, or risk making admissions that would result in the term being found to be reasonably well understood.