CAFC Finds Proposed Claim Construction Unsupported by Disclosure

The Federal Circuit in Steuben Foods, Inc. v. Nestle, Inc. (Appeal No. 2017-1290, Fed. Cir., decided March 13, 2018) rejected the patent owner’s claim construction as impermissibly restricting the claim term to a specific embodiment disclosed in the specification.  Based on this claim construction, the Court affirmed the final decision of the Patent Trial & Appeal Board in the appealed inter partes review finding the claims to be unpatentable as obvious.

The claim term at issue is “sterilant concentration levels” in US6,475,435.  An annotated copy of a figure used by the Court is reproduced below.  This figure shows a sterilization tunnel used for packaging food.  The sterilization tunnel is pressurized to create a flow of sterile air out of the tunnel to prevent contaminants from flowing into the tunnel.  The tunnel is divided into the color-coded zones shown below and each zone has a different purpose (the fourth zone provides bottles, the first zone provides drying, etc.).  The claims are directed toward maintaining “different sterilant concentration levels in the plurality of zones.”

CAFC Finds Proposed Claim Construction Unsupported by Disclosure

In the IPR, the Board construed “sterilant concentration levels” to be levels measured “at any point within the sterilization tunnel – including ‘residual’ concentration on bottle surfaces.”  On appeal, the patent owner argued that this construction is so broad that it could cover the concentration at any point, including at a random droplet on a container, and argued that the term should instead be construed as “the amount of sterilant in the volume of pressurized gas within the zone.” 

The Court rejected this argument as impermissibly restricting the claim term to a specific embodiment disclosed in the specification.  Specifically, the Court noted that the specification does discuss “different concentration levels of gas laden sterilant,” but one section of the specification also discusses “residual concentration” of sterilant on bottle surfaces.  The Court affirmed the Board’s conclusion that, since “neither the claims nor the specification limit how or where…the sterilant concentration levels should be assessed,” the broadest reasonable interpretation must include both gas laden concentrations and residual sterilant concentrations on bottle surfaces.

In general, explicit definitions/descriptions of claim terms should be considered at the time of drafting the patent application, especially if the drafter suspects a term to be important and/or open to an overly broad construction.  Many considerations must be weighed to make that decision at the time of preparation, but with the benefit of 20/20 hindsight, such a definition/description to directly limit the specific term “sterilant concentration levels” to concentration levels of gas laden sterilant may have resulted in a different outcime in the specific fact pattern of this Federal Circuit appeal.