Claim Construction Overturned By Improper Reliance on Extrinsic Evidence

Desa IP LLC v. EML Technologies, LLC (06-1168) - January 4, 2007 (Nonprecedential)

In an interesting case, the CAFC overturned the lower court's claim construction when it relied on expert testimony in construing various means-plus-function terms during a Markman hearing. Despite the CAFC previously questioning Cybor's de novo standard in the Amgen case, the court showed little deference in this case to the lower court's claim construction and to the expert testimony provided to the court:

Although the district court seemed to rely upon expert testimony, we note that its conclusion could have been reached without the aid of extrinsic evidence . . . We conclude that [the district court] erred in relying upon Professor Massengill's expert testimony. In doing so, the district court construed each disputed claim term by simply referring to various passages in the specification that corresponded to portions of Figures 2A and 2B, which depict the preferred embodiment. Expert testimony in conflict with the intrinsic evidence, however, should have been accorded no weight.

[N]ot only does the specification of the '066 patent repeatedly refer to the passive infrared sensors Q1 and Q2 as the "sensors," it even explicitly states that "[t]he sensors Q1 and Q2 are each coupled to a detector portion 43 of the circuit," and then goes on to describe the additional functions of the circuit - i.e., selecting and amplifying the "signals most likely to correspond to infrared signals from a human body." Col.3 ll.34-35, 38-39. Because the intrinsic evidence clearly sets forth the corresponding structure for "sensor means," it was improper to rely upon contrary extrinsic evidence to construe this term.

The CAFC went further, in a footnote, to state that the testimony itself was wrong in the court's eyes:

In any event, we reject with Professor Massengill's testimony that the "selection circuitry" is part of the "sensor means." Rather, the passive infrared sensors Q1 and Q2 detect motion, while the pulse-counting feature and other parts of the circuit are used to decide whether the lamp switches to the brighter level of illumination in response or whether the detected motion is ignored.

VACATED AND REMANDED