In Sonix Technology Co., Ltd. v. Publications International, Ltd., No. 16-1449 (Fed. Cir. Jan. 5, 2017), the Federal Circuit reversed the district court's decision that the claim term "visually negligible" rendered the claims indefinite.

Sonix brought suit against Publications International, alleging infringement of U.S. Patent No. 7,328,845, which is directed to using a "graphical indicator" to encode information on the surface of an object that can be read using an optical device to output additional information. The asserted claims of the '845 patent recite that the indicator is "visually negligible." The district court granted summary judgment, finding the term "visually negligible" indefinite, concluding that it relied on the user's perception with no objective standard to measure the scope of the term.

Sonix appealed and the Federal Circuit reversed, finding that "visually negligible" was not purely subjective and a skilled artisan would understand its scope. The court explained that whether something is "visually negligible" involves "what can be seen by the normal human eye," which provides an objective baseline to interpret the claims. According to the court, the term's scope was explained in the examples and written description. The court also found persuasive that Publications International did not question the definiteness of "visually negligible" during the first several years in litigation and both parties' experts applied this term to prior art and accused products.

The court clarified the scope of its opinion, explaining that examples and requirements in a specification do not always render a claim definite, and also that an expert applying a term without difficulty does not "render a claim immune from an indefiniteness challenge." Rather, "whether a claim is indefinite must be judged 'in light of the specification and prosecution history' of the patent in which it appears."

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