Durr Systems sued EFC Systems for infringing five patents related to rotary atomizers used for applying particulate paints. These patents aim to improve color matching by ensuring paint droplets lie flat on surfaces through specific bell cup designs. The core dispute involved two claim limitations: whether the bell cup's overflow surface must be strictly conical or if slight curves are permitted, and whether the 'rear cover' must be a separate piece attached to the bell cup or if it can be formed integrally. The district court granted summary judgment of noninfringement to EFC, ruling that EFC's slightly curved bell cup did not meet the 'conical' requirement and that its single-piece rear cover did not meet the 'attached' requirement. The district court also excluded Durr's expert testimony, finding the expert lacked the necessary technical background in atomizer design. Durr appealed both the claim construction and the expert exclusion.
The Federal Circuit reviewed the claim construction de novo. Regarding the term 'generally conical' or 'substantially conical,' the court held that words of approximation are commonly used in patent claims to avoid strict numerical boundaries. The court reasoned that the plain meaning of these terms allows for some deviation from a perfect cone, including undulations or curved portions. The court found that the district court's construction, which excluded all curves, was too narrow and inconsistent with the specification and prosecution history, which only distinguished the patent from a prior art reference with dramatic undulations. Regarding the term 'rear cover attached to the bell cup,' the court applied the plain and ordinary meaning of 'attached,' which encompasses joining, fixing, or connecting. The court determined that this term is agnostic to the method of attachment and does not require the components to be separate pieces. The court noted that nothing in the dependent claims or specification limited the independent claims to separate pieces. Finally, the court reviewed the exclusion of the expert witness for abuse of discretion. The court affirmed the district court's definition of a person of ordinary skill in the art (POSA) as someone with experience in atomizer design and fluid dynamics. Because the expert, Mr. Dattilo, lacked specific experience in designing rotary atomizers, the court agreed that his testimony was not relevant or reliable for the issues at hand.
The case is remanded to the district court for further proceedings consistent with the Federal Circuit's corrected claim construction. The summary judgment of noninfringement is vacated, meaning the dispute over whether EFC's bell cup infringes the patents will now proceed, likely to a jury trial. However, Durr cannot rely on the testimony of Mr. Dattilo to prove infringement or validity, as the expert exclusion stands. This decision clarifies that patent claims using 'generally' or 'substantially' regarding shape are not limited to perfect geometric forms and that 'attached' does not mandate separate manufacturing.
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