Motion to Strike Expert Testimony Granted to Preclude Expert's "Logic Analysis" to Determine the Physical Structure of a Circuit but Expert Permitted to Opine That Logic of Accused Circuit Corresponds to Patent

August 7, 2013

Plaintiff Cobra International, Inc. ("Cobra") filed a patent infringement action against several defendants, including BCNY International ("BCNY") alleging infringement of a patent for the design of lighted footwear. The defendants create children's shoes that have a small electrical module with an integrated circuit mounted on a chip. As explained by the district court, "[t]he chip, which is mounted on a circuit board and covered by a dot of epoxy, is a small rectangular piece of silicon less than one-quarter of an inch across on which the various electrical components are formed through a multi-layer process. The chip is connected to a switch, a battery, and a number of LED lights on the outside of the shoe. When the switch is triggered, the LEDs flash in a pattern for a short period and then stop."

The Defendants moved to exclude two of Cobras expert opinions: (1) the opinion that the schematics relied on by Defendants do not accurately represent the circuit in the accused product; and (2) the opinion that the circuit in the accused product uses the same "logic" as Cobra's patent.

As summarized by the district court, "[t]he crux of Defendants' position is that Anthony [Cobra's expert], unlike Defendants' expert, never physically analyzed the circuit on the accused chip: Anthony never performed a detailed physical examination of the accused circuit, never reverse engineered the circuit design on the chip in the accused products, never analyzed the chip under a microscope, never identified the various circuit components, and never mapped those circuit components to the corresponding depictions in Defendants' circuit diagrams. This 'look under the hood' approach that Anthony failed to employ is, according to Defendants, 'essential to any effort to identify the physical structure and elements of an integrated circuit like the one in the accused products.'"

In response, Cobra asserted that its expert determined the logic circuit--as opposed to the physical circuit that Defendants focus on--simply by observing the accused product's LED flashing pattern. According to Cobra, its expert's logic analysis method permitted reverse engineering the circuit by cycling through all possible inputs, observing the output, and creating a "truth table." Based on the content of the truth tables, Cobra contended it was possible to determine the logic circuit elements and their functional interrelationship. As further explained by the district court, "Cobra's position is that Anthony reverse engineered the logic of the accused product and determined that the logic of the accused product necessarily matches the logic of the patent. The Court does not construe Cobra's position to be at all related to the physical structure of the circuit in the accused product."

The district court noted that "the problem with the parties' arguments is that they speak past each other. Defendants focus exclusively on the physical structure of their circuit and how Anthony's method of "logic analysis" could not possibly provide a basis for his opinion that the circuit diagrams do not accurately reflect what is in the accused product."

The district court then focused on Cobra's expert's analysis and stated that it did not interpret Cobra's expert opinion "as speaking to the physical structure of the circuit in the accused product. Rather, the Court construes Anthony's opinion as expressing his view that, based on logic analysis of the accused product's external lights, the logic of the accused product must necessarily correspond to the logic of the patent regardless of the physical structure of the circuit in the accused product."

The district court considered that this interpretation was consistent both with Cobra's expert's testimony and Cobra's response to Defendants' motion to exclude Anthony's testimony, which did not address Cobra's expert's ability to render an opinion on the physical structure of the circuit. The district court explained that "Cobra's response expressly distinguishes between physical circuits and logic circuits, stating that '[Defendants] make [their] case by confusing physical circuits with logic circuits. . . . To determine the physical circuit in a chip, one must look at the physical circuit. But . . . the [patent] illustrates and describes a logic circuit.'"

The district court found the Defendants argument unpersuasive because "[a]t no point do Defendants argue against the reliability of Anthony's "logic analysis" method as applied to determining the logic of a circuit. Rather, Defendants focus exclusively on the method's inability to provide insight as to the physical structure of the circuit in the accused product. To the extent Defendants argue that Anthony's method of "logic analysis" has not been proven to be a reliable method of determining the physical structure of a circuit, the Court agrees. Anthony's testimony will be excluded to the extent that it purports to state a view on whether Defendants' diagrams accurately represent the circuit in the accused product. However, to the extent Anthony opines on the logic of the accused circuit and the correspondence of that logic to the logic of the patent, Defendants' motion to exclude Anthony's testimony is denied."

Cobra International, Inc. v. BCNY International, Inc., et al., Case No. 05-61225-CIV-MARRA/HOPKINS (S.D. Fla. July 29, 2013)

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