Imaginal Systematic, LLC v. Leggett & Platt

Addressing the issue of whether the district court properly relied on dictionary definitions when construing a negative claim limitation that was the basis for a summary judgement of non-infringement, the U. S. Court of Appeals for the Federal Circuit answered in the affirmative, holding that courts can rely on dictionaries so long as the dictionary definition does not contradict any definition found in or ascertained by a reading of the intrinsic evidence. Imaginal Systematic, LLC v. Leggett & Platt, Case No. 14-1845 (Fed. Cir., Nov. 10, 2015) (O’Malley, J.).

Leggett & Platt (L&P) designs and manufactures equipment used to assemble box springs. Imaginal Systematic (Imaginal) filed suit against L&P alleging that an L&P stapling machine infringed an Imaginal patent directed toward a process of assembling box springs.

The district court granted summary judgement of non-infringement on the grounds that L&P stapling machine that used a camera as an input to a computer does not satisfy a claim limitation requiring the stapler not use vision- or sight-based control. Imaginal appealed, arguing that the district court improperly constructed the negative claim limitation to obviate infringement. Imaginal asserted that the district court defined the negative limitation too broadly.

The asserted claim requires moving a fastener tool “without the use of a vision guidance tool.” Since such a negative limitation is exclusionary rather than inclusionary, the typical arguments regarding claim breadth asserted by parties in litigation are reversed. Typically, patentees will argue for a broad construction of a claim element so as to encompass an accused product, while accused infringers will seek a narrow construction so as to avoid infringement. However, when a negative limitation is in issue, it is the patentee who will typically argue for a narrow construction in order preserve the claim scope, while the accused infringer will argue for a broader construction which tends to limit the claim scope.

Patentees frequently act as their own lexicographers, which is why courts initially refer to the specification when construing claim terms. However, when the specification alone is insufficient for claim construction, courts are free to rely on dictionaries. In this case, the specification did not explicitly define the term “vision guidance tool,” and so the court looked to the ordinary dictionary meaning of the words “vision” and “guidance.” The court’s construction resulted in a construction of a negative claim limitation that was sufficiently broad to exclude the accused product.

Imaginal’s argument that the limitation should be construed to only exclude the vision guidance system disclosed in the specification failed because while the patentee could have defined the term such that it was restricted to a specific embodiment, it did chose not do to.

Practice Note: If required to introduce a negative claim limitation during prosecution, practitioners should try to insure the intrinsic evidence will support a narrow construction.